THE BLOOD PRESSURE RESPONSE OF TWO POPULAR KETTLEBELL ROUTINES
John Douglass Martin
B.S., Southern Illinois University, Carbondale, 2006
THESIS
Submitted in partial satisfaction of
the requirements for the degree of
MASTER OF SCIENCE
in
KINESIOLOGY
(Exercise Science)
at
CALIFORNIA STATE UNIVERSITY, SACRAMENTO
SPRING
2012
THE BLOOD PRESSURE RESPONSE OF TWO POPULAR KETTLEBELL ROUTINES
A Thesis
by
John Douglass Martin
Approved by:
__________________________________, Committee Chair
Dr. Roberto Quintana
__________________________________, Second Reader
Dr. Daryl Parker
____________________________
Date
ii
Student: John Douglass Martin
I certify that this student has met the requirements for format contained in the University format
manual, and that this thesis is suitable for shelving in the Library and credit is to be awarded for
the thesis.
__________________________, Graduate Coordinator ___________________
Dr. Michael Wright
Date
Department of Kinesiology
iii
Abstract
of
THE BLOOD PRESSURE RESPONSE OF TWO POPULAR KETTLEBELL ROUTINES
by
John Douglass Martin
Introduction
Cardiovascular Disease (CVD) has been the leading killer of adults in the United States for nearly
80 years and hypertension (HTN) is the chief indicator of future cardiovascular complications
(Lloyd-Jones et al., 2010). Fortunately, even small decreases in BP can reduce all cause
mortality, death due to stroke, and death due to CVD by 7%, 14%, and 9& respectively (D. W.
Jones & Hall, 2004; Sharman & Stowasser, 2009). Exercise has repeatedly been shown to reduce
BP acutely (Pescatello et al., 2004; Sharman & Stowasser, 2009; Wallace, 2003). This immediate
decrease in BP is called post-exercise hypotension (PEH) and has been reported to last upwards
of 22 hours (Quinn, 2000). As of today, only walking, jogging, running, and cycling have been
studied extensively but the ACSM recommends that any activity that uses large muscle groups,
can be maintained continuously, and is rhythmical and aerobic in nature” be used as the primary
BP reducing modality for those with HTN (Pescatello, et al., 2004). One such mode of exercise
that meets that requirement is kettlebell swings. The use of kettlebells have been reported to have
a similar cardiovascular response to moderate-vigorous running(Farrar, Mayhew, & Koch, 2010).
iv
The question can then best asked if a single bout of kettlebell exercise is sufficient enough to
elicit a significant PEH response.
The purpose of this study is to determine if two popular kettlebell routines produce a
significant PEH response. It was hypothesized that both KB exercise routines would produce
clinically and statistically significant decreases in systolic blood pressure (SBP) and diastolic
blood pressure (DBP) post-exercise during recovery.
Methods
Eight resistance trained pre-hypertensive and HTN males performed a randomized cross-over
designed study which included 12 minutes of continuous two-handed swings (THS), three sets of
a 6 exercise circuit (CIR), and a resting control (CON). Participants rested for 20 minutes after
exercise before initial post-exercise BP and heart rate (HR) were recorded. Measurements
occurred every 30 minute for 120 minutes. Statistical significance was determined by two-way
ANOVA with repeated measures and TUKEY post-hoc analysis. Clinical significance was
determined as a reduction in SBP <130 mmHg or DBP < 80 mm Hg.
Results
CIR and THS significantly lowed SBP by -8.5 ± 4.5 and -9.3 ± 4.4 mmHg, respectively, (
p<0.05). The reductions in SBP values were also clinically significant during all post-exercise
measurements for CIR and during minute 0, 60, 90, & 120 for THS. A clinically significant
decrease in DBP occurred at minute 30 and 60 for CIR. Heart rate significantly elevated above
CON and rest during minute 0 for CIR and THS (23 ± 4.7 and 21 ± 4.7 bpm respectively, p <
0.001)
v
Conclusions Reached
The purpose of this study was to determine if two popular kettlebell exercise routines were
significant enough to produce significant PEH responses. Our hypothesis was correct as both
routines reduced blood pressure to values that were both clinically and statistically significant.
These results indicate that kettlebell exercise is an effective modality for decreasing blood
pressure acutely in resistance trained males who are pre-hypertensive or hypertensive.
_______________________, Committee Chair
Dr. Roberto Quintana
_______________________
Date
vi
DEDICATION
-
To Dr. Quintana, who taught me to see the bigger picture. You explained to me that life
is a marathon and occurs in phases. That resting and enjoying life is equally as important
as meeting deadlines. You showed me that investing my life in others is of more benefit
to myself and others than any other selfish pursuit.
-
To my parents, who instilled in me the importance of having both character and
accomplishments.
-
To my sister, who continues to be my “gold standard” of hard work and dedication.
-
To my wife. Who encourages, motivates, and challenges me to be a better man.
-
To my LORD, whom without, I am nothing.
vii
TABLE OF CONTENTS
Page
Dedication ........................................................................................................................ vii
List of Tables ......................................................................................................................xi
List of Figures .................................................................................................................. xii
Chapters
1. INTRODUCTION ........................................................................................................... 1
Statement of Problem ....................................................................................................... 2
Statement of Purpose ....................................................................................................... 3
Significance of Thesis ...................................................................................................... 3
Hypotheses ....................................................................................................................... 4
Assumptions..................................................................................................................... 4
Limitations ....................................................................................................................... 5
Delimitations .................................................................................................................... 5
Definitions........................................................................................................................ 5
2. REVIEW OF LITERATURE .......................................................................................... 7
Hypertension .................................................................................................................... 7
Description. ............................................................................................................ 7
Statistics and Risks. ................................................................................................ 8
Treatment. .............................................................................................................. 9
Clinical Significance. ........................................................................................... 10
Post Exercise Hypotension............................................................................................. 11
viii
Description. .......................................................................................................... 11
Endurance Exercise ........................................................................................................ 12
Intensity and PEH................................................................................................. 12
Duration and PEH. ............................................................................................... 14
Resistance Exercise ........................................................................................................ 14
Alternative Modes of Exercise ....................................................................................... 15
Kettlebells............................................................................................................. 16
3. METHODS.................................................................................................................... 18
Research Design............................................................................................................. 18
Participants..................................................................................................................... 18
Instrumentation .............................................................................................................. 19
Procedure ....................................................................................................................... 19
Familiarization Period. ......................................................................................... 19
Experimental Trials. ............................................................................................. 19
Statistical Analysis. .............................................................................................. 20
Clinical Significance. ........................................................................................... 21
4. RESULTS...................................................................................................................... 22
Performance Outcomes .................................................................................................. 22
Hemodynamic Response ................................................................................................ 22
Systolic Blood Pressure. ....................................................................................... 22
Diastolic Blood Pressure. ..................................................................................... 25
Heart Rate Responses..................................................................................................... 27
ix
5. DISCUSSION ............................................................................................................... 30
Significant Outcomes ..................................................................................................... 30
Mechanism ..................................................................................................................... 31
Relevance of Findings .................................................................................................... 32
Future Research ............................................................................................................. 33
Conclusion ..................................................................................................................... 34
Appendix A Consent to Participate ................................................................................... 35
Appendix B Pre-Test Instructions ..................................................................................... 38
Appendix C Participation Screening Questionnaire .......................................................... 39
References ......................................................................................................................... 43
x
LIST OF TABLES
Page
Table 1. Characteristics of the Participants .................................................................................. 18
Table 2. The Participants’ Performance Outcomes ..................................................................... 22
Table 3. Hemodynamic Responses of Participants ...................................................................... 29
xi
LIST OF FIGURES
Page
Figure 1. Systolic blood pressure (SBP) before and after exercise. .............................................. 24
Figure 2. Diastolic blood pressure (DBP) before and after exercise............................................. 26
Figure 3. Heart Rate (HR) before and after exercise .................................................................... 28
xii
1
Chapter 1
Introduction
Everyday nearly 2300 Americas die from cardiovascular disease (CVD) which equals
one death every 38 seconds (D. W. Jones & Hall, 2004). A number of factors are associated with
CVD but high blood pressure (systolic blood pressure (SBP) ≥ 140 mm Hg and/or a diastolic
blood pressure (DBP) ≥ 90 mm Hg) is the most prevalent with nearly two-thirds of American
adults (≥ 20 years of age) being classified as hypertensive (HTN) or pre-hypertensive (sBP >
120-139/ dBP>80-89) (D. W. Jones & Hall, 2004). Fortunately, blood pressure levels can be
reduced to healthy levels though the use of medication, dietary changes, and exercise.
While prescription drugs have repeatedly been shown to be effective in controlling HTN;
they must be taken daily, and are associated with a host of side effects including drowsiness,
depression, impotence, headaches, diarrhea, and fever (D. W. Jones & Hall, 2004). The
American College of Sports Medicine (ACSM) recommends 30 or more minutes of continuous or
accumulated endurance exercise of a moderate intensity (40-60% V02R) on most or all days of
the week supplemented with resistance exercise in order to chronically lower blood pressure
("American College of Sports Medicine. Position Stand. Physical activity, physical fitness, and
hypertension," 1993; Pescatello, et al., 2004). Meta-analysis of studies utilizing the ACSM
cardiovascular exercise recommendations were shown to reduce resting blood in previously
hypertensive (7.4 mm Hg systolic and 5.8 mmHg diastolic) and normotensive (2.6 mm Hg SBP /
1.8 mm Hg DBP) participants independent of any other anti-hypertensive intervention (Fagard,
2001) including medication. Meta-analysis of studies implementing only resistance training also
demonstrated significant decreases in blood pressure but of a lesser magnitude (3 mm Hg / 1.8
2
mm Hg) than cardiovascular exercise, indicating that both endurance and resistance exercise over
time are effective at chronically lowering resting blood pressure (Pescatello, et al., 2004).
In addition to the chronic effect of exercise on blood pressure, a single bout of exercise is
sufficient to elicit a significant decrease in blood pressure below baseline values for up to 22
hours (Quinn, 2000). This decrease in blood pressure following a single bout of exercise is
termed post-exercise hypotension (PEH) and has been well documented occurring after both
cardiovascular endurance and resistance exercise, although, the optimal intensity, time, and type
of exercise for PEH is still highly debatable (Pescatello, et al., 2004).
Statement of Problem
The optimal intensity for PEH is unknown but several studies have reported that exercise
intensities exceeding those recommended by the ACSM (40 – 60% VO2R) have produced greater
magnitude PEH results from endurance training (Nybo et al., 2010; Quinn, 2000) while other
studies concluded that exercise intensity has little to no effect on PEH response (Graziela C.
Simones, 2010; Polito, 2003). The ACSM recommend ≥ 30 minutes of moderate intensity
physical activity a day which can be broken down into shorter intervals lasting as little as 10
minute (D. W. Jones & Hall, 2004; Pescatello, et al., 2004). Using interval exercise as a model,
several studies have produced clinically significant PEH responses from bouts of exercise from
10 minutes to 3 minutes in length (Pescatello, et al., 2004; Wallace, 2003). While only a few
modes of exercise have been studied for the BP response, the ACSM recommend that in addition
to endurance exercise, “ any activity that uses large muscle groups, can be maintained
continuously, and is rhythmical and aerobic in nature” be used as the primary BP reducing
modality for those with HTN (Pescatello, et al., 2004). One such exercise that meets these
recommended criteria is kettlebell swings.
3
The kettlebell (KB) is cannonball shaped iron hand weight with a handle. Also known as
the “girya” in Russian, kettlebells date back to the early 1700’s and were first introduced to the
US in a 1913 issue of “Hercules” (Tsatsouline, 2006). Their popular resurgence in the United
States is due primarily to exercise programs like CrossFit, Pavel Tsatsouline’s workshops, and
exercise patrons looking to increase strength and endurance while reducing body fat (Farrar, et
al., 2010). Unfortunately, very little scientific research currently exist outside of a 2010 study
that suggested that KB swings are a valid way to increase cardiovascular fitness based on the
oxygen cost of a 12 minute routine (Farrar, et al., 2010) . Based on the 2010 KB study, anecdotal
evidence, and the open recommendation by the ACSM regarding exercise and PEH response, a
study on the effects of KB exercise and BP is warranted.
Statement of Purpose
The primary purpose of this study was to determine if two popular kettlebell routines are
sufficient to elicit a clinically significant PEH response in current resistance trained prehypertensive and hypertensive men.
Significance of Thesis
CVD has been the leading killer of adults in the United States for nearly 80 years and
hypertension is the chief indicator of future cardiovascular complications (Lloyd-Jones, et al.,
2010). While pharmacological remedies are often prescribed in conjunction with exercise,
exercise and physical activity alone have been shown to reduce blood pressure to healthy levels
both chronically and acutely. Unfortunately, most research that has been conducted has only
utilized walking, running, cycling, or standard resistance exercises (Pescatello, et al., 2004).
4
Over the past decade, the use of kettlebells have become increasingly popular but
currently, few studies exists documenting the cardiovascular response to their use. By examining
the BP response of two popular kettlebell routines, it is possible that those attempting to control
their blood pressure though exercise will have an alternative to standard cardiovascular and
strength training exercises.
Hypotheses
1. Both KB routines would produce clinically and statistically significant decreases in SBP
and DBP post-exercise during the 120 minute recovery period.
2. The participants’ HR would vary significantly compared to CON during CIR and THS
trials post-exercise.
Assumptions
1. All participants answered the screening questionnaire truthfully.
2. All participants complied with pre-testing procedures.
3. The participants had no cardiovascular abnormalities or physical limitations.
4. All participants gave maximum effort during both KB routines.
Limitations
1. The participants’ truthful adherence to pretest protocols.
2. The weight of the kettlebells used during testing was not relative to the participants’
prior KB experience or bodyweight.
3. The intensity of the freeform kettlebell exercises.
5
Delimitations
1. This study was limited to resistance trained non-medicated Type-I hypertensive and
pre-hypertensive males aged 25-32.
2. Participants self-selected exercise intensity (tempo of swings and length of rest
between sets).
3. This study only measured acute 2-hour BP recovery response.
4. This study only measured acute 2-hour recovery HR.
Definitions
1. HR: Hear Rate in beats per minute
2. BP: Blood Pressure or systolic / diastolic
3. SBP: Systolic Blood Pressure
4. DBP: Diastolic Blood Pressure
5. HTN: Hypertension or possessing either systolic blood pressure greater ≥ 140 mm
Hg /pressure (systolic blood pressure (SBP) and/or a diastolic blood pressure ≥ 90
mm Hg.
6. PEH: Post-exercise hypotension: The acute decrease in blood pressure below resting
values following a single bout of exercise.
7. VO2max: Maximum oxygen uptake and aerobic capacity
8. Clinical Significant PEH: A decrease in SBP < 130 mm Hg and/or a decrease in
DBP < 80 mm Hg.
9. TPR: Total Peripheral Resistance
6
10. 1-RM: Maximum weight lifted for one repetition
7
Chapter 2
Review of Literature
Hypertension
Description.
The American Heart Association (AHA) and the Joint National Committee on
Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC) define
Hypertension (HTN) or Stage I HTN as possessing a systolic blood pressure (SBP) greater than ≥
140 mmHg and/or a diastolic blood pressure (DBP) ≥ 90 mmHg or currently taking antihypertension medication (D. W. Jones & Hall, 2004; Lloyd-Jones, et al., 2010). Optimal blood
pressure is defined as < 115 mm Hg systolic and <75 diastolic while “pre-hypertensive” is
defined as 120 – 139 mmHg systolic and 80-89 mmHg diastolic. Blood pressure classified as
pre-hypertensive is not considered diseased but is aptly named in order to identify parties who are
at a greater risk for developing hypertension (D. W. Jones & Hall, 2004). In order to be properly
classified, the JNC recommends that two seated measurements be taken on separate visits in order
to reduce possible errors such as the “white coat” syndrome. If both measurements fall into the
same criteria then the patient can then be accurately classified (D. W. Jones & Hall, 2004).
Assessing one’s BP has three primary purposes; to identify lifestyle and other
cardiovascular risk factors, to discover identifiable diseases that cause HTN, and to determine if
there is any internal organ damage or CVD (D. W. Jones & Hall, 2004). Hypertension is caused
by a number of factors including lifestyle; Type II diabetes, High LDL, Low HDL, family
history, obesity, tobacco use, dietary factors (high sodium, low potassium, high alcohol
consumption), and physical inactivity (D. W. Jones & Hall, 2004). Other causes of HTN are
8
disease related ( i.e. chronic kidney disease, Cushing syndrome, sleep apnea, drug related
interactions, obstructive uropathy, primary aldosteronism, and thyroid/parathyroid disease) (D.
W. Jones & Hall, 2004). In addition to these causes, Vasan, et al. reported that as people age,
their SBP will increase even if they are normotensive at age 55 and 65. In fact, it is estimated that
90% of normotensive men and women will be hypertensive by the age of 80 and 85 respectively
(Vasan et al., 2002).
Statistics and Risks.
Cardiovascular Disease (CVD) kills upwards of upwards of 7.3 million people worldwide
and nearly 2300 people each day in the United States (D. W. Jones & Hall, 2004; Lloyd-Jones, et
al., 2010). The JNC calls the link between blood pressure and CVD events “continuous,
consistent, and independent of all other risk factors” and indicates that “the higher the BP, the
greater is the chance of heart attack, HF, stoke, and kidney disease” (D. W. Jones & Hall, 2004).
In 2010 it was reported that over 1 billion people around the world and approximately 1 out of 3
of adults over the age of twenty in the United States had high blood pressure (Lloyd-Jones, et al.,
2010). While medical treatments and early detection have decreased the age-adjusted death rate
for stoke and coronary heart disease nearly 60% since 1972, the occurrences of heart disease and
end-stage renal disease continue to rise indicating that the fight to control BP is far from over (D.
W. Jones & Hall, 2004).
Examining the direct effects of HTN, the JNC reports that deaths from ischemic heart
disease (IHD) and stroke increase linearly when blood pressure is above 115 mmHg systolic and
≥75 mmHg diastolic. More specifically, the mortality rates are doubled for IHD and stroke every
20 mmHg systolic or 10 mmHg diastolic that BP levels are above the optimal level. The dangers
9
of elevated BP are not just reserved for those who are hypertensive either, the Framingham Heart
Study concluded that pre-hypertensives with BP levels from 130-139 mm Hg sBP and 85 to
89mm Hg dBP are at double the risk of developing CVD than those with optimal BP levels.
Treatment.
Patients classified as HTN generally undergo a combination of three treatments in order
to decrease and regulate their BP to healthy levels; medication, diet, and exercise. The JNC
recommends that all Stage I hypertensives be prescribed medication in conjunction with dietary
changes and regular exercise (D. W. Jones & Hall, 2004). While medications are generally a
time efficient way to regulate blood pressure, two-thirds of HTN patients are required to ingest
more than one drug in order to accurately control their BP (D. W. Jones & Hall, 2004). The ease
of administration of prescription drugs is not without a cost though. The drugs must be must be
taken daily, in most cases for the remainder of the HTN patients life, and are associated with such
side effects as drowsiness, depression, impotence, headaches, diarrhea, and fever. Poor diets and
lack of physical activity lead many HTN patients to choose and become dependent on
prescription drugs for controlling the blood pressure.
Dietary modifications, such as the DASH (Dietary Approaches to Stop Hypertension)
diet are also made in order to help control BP. The DASH diet is high in fruits, vegetables, lowfat diary and reduced cholesterol, saturated, and total fat. This diet is contradictory to the average
US male and female’s diet that consumes nearly 190% the maximum recommended daily sodium
intake. In fact, only 25% of Americans consumes the minimum servings of 5 servings of fruits
and vegetables a day (D. W. Jones & Hall, 2004).
10
Lastly, at least 30 minutes of moderate intensity exercise is prescribed to hypertensive
patients and non-hypertensive patients alike. Unfortunately, only 20% of the US population meets
the recommended amount of daily physical activity (D. W. Jones & Hall, 2004) but that does not
make exercise any less effective. Exercise has been shown to have minimal side effects, minimal
coast, and has been proven to decrease a number of CVD risk factors. For these reasons, The
AHA, ACSM, & JNC7 all recommended regular exercise for the prevention and treatment of
HTN (D. W. Jones & Hall, 2004; Lloyd-Jones, et al., 2010; Pescatello, et al., 2004).
In 2003, the ACSM assessed 68 studies where initial resting BP levels were recorded and
determined that the average decrease in BP was 7.4mm Hg sBP / 5.8 mm Hg dBP in
hypertensive participants and 2.6 mm Hg sBP / 1.8 mm Hg dBP in normotensive participants
when accounting for control and sample size (Pescatello, et al., 2004). These findings and the
Australian Position Stand all indicate that the magnitude of PEH response is dependent in part on
the severity of pre-test BP levels. (Pescatello, et al., 2004; Sharman & Stowasser, 2009).
Clinical Significance.
The World Health Organization (WHO) and the Society of Hypertension (ISH)
recommend that “even small reductions in blood pressure are associated, in long-term, large-scale
population studies, with a reduction risk of cardiovascular disease” (Whitworth, 2003). It was
also reported by the JNC and the Australian Association for Exercise and Sports Science that
reductions as little as 5mm Hg in systolic blood pressure can reduce all cause mortality, death due
to stroke, and death due to CVD by 7%, 14%, and 9& respectively (D. W. Jones & Hall, 2004;
Sharman & Stowasser, 2009). While no optimal standard for PEH magnitude is agreed upon, the
consensus is that, a decrease of any magnitude in decrease is better than none at all.
11
Although no exact values currently exists, the WHO and ISH give recommend values for
clinical significance in low, moderate, and high risk patients with HTN. Low to moderate risk
patients with HTN should only aim to reduce their SBP below 140 mm Hg since systolic is of
greater importance in these populations (Kannel, 2000; Whitworth, 2003). In high risk HTN
patients, 130/80mm Hg (SBP/DBP) should be the goal (Whitworth, 2003). Several studies have
determined that both cardiovascular endurance and resistance training are effective at acutely
reducing sBP to these clinically significant levels in high risk populations including those with
chronic heart failure, type II diabetes, and the elderly (Brandao Rondon et al., 2002; Pina et al.,
2003; Simoes, Moreira, Kushnick, Simoes, & Campbell, 2010). Although not reported to be
statistically significant, several studies have shown clinically significant reductions in BP based
on the Who and ISH standard. Simones et. al. reported that resistance training in a high risk
population with type II diabetes reduced SBP 9.5 +/- 11.1 which meets the WHO and ISH
standard for clinical significance (Simones et. al, 2010). Other studies have also concluded that
both cardiovascular endurance and resistance training are effective at reducing blood pressure to
clinically significant levels in high-risk populations (Brandao Rondon, et al., 2002; Pina, et al.,
2003).
Post Exercise Hypotension
Description.
In addition to the chronic benefits of exercise, an acute decrease in BP also results from a
single bout of exercise and has been reported to last upwards of 22 hours (Quinn, 2000). This
decrease in blood pressure below baseline values after exercise is called post-exercise
hypotension and was first seen in 1897 following a 400 yard dash (Hill, 1897). What was
originally thought to be the chronic effect of endurance training may actually be an accumulating
12
acute decrease in blood pressure (Pescatello, et al., 2004). This acute response when compared to
weekly training was found to be as effective in decreasing BP values. A 23 study meta-analysis
by Pescatello examining the ambulatory blood pressure response of dynamic exercise concluded
that dynamic exercise was effective for both chronic and acute BP decreases (Pescatello, et al.).
The current ACSM position stand recommends the optimal training FITT (Frequency,
Intensity, Time, & Type of exercise) for the chronically decreasing BP as ≥ 30 minutes of
continuous or accumulated endurance exercise at moderate intensity (40-<60% of VO2 Reserve)
on most or all days of the week supplemented with resistance exercise (Pescatello, et al., 2004).
This FITT has been supported and recommended by the both the JNC and the American Heart
Association, unfortunately, the ACSM has not given such a steadfast recommendation as for the
optimal FITT in order to elicit the greatest acute BP response but recommends that further studies
be conducted regarding intensity, duration, and type (Pescatello, et al., 2004).
Endurance Exercise
Intensity and PEH.
The optimal intensity of exercise needed to elicit the greatest acute PEH response is
currently under much debate. Several studies have concluded that lower intensity exercise (<60%
VO2max) is optimal for PEH response but also state that the intensity of exercise does not play a
major role in determining the magnitude or duration of PEH (Pescatello, et al., 2004; Wallace,
2003). After comparing the PEH response of hypertensive and normotensive participants after
cycling at 75% VO2max and 50% VO 2max for 30 minutes on separate days; Macdonald and
colleagues also concluded that lower intensity exercise is optimal for PEH but also reported that
the difference between intensities was non-significant (p ≤ 0.05) (J. MacDonald, MacDougall, &
Hogben, 1999). In a similar study utilizing the same exercise protocol but measuring BP for 24
13
hours post exercise instead of 60 minutes, Quinn concluded that exercise intensity does indeed
play a significant role (Quinn, 2000). The higher intensity bout of exercise ( 75% VO2max vs.
50%VO2max) produced a SBP PEH response that was more than double that of lower intensity
exercise (9 mm Hg vs. 4 mm Hg) and produced a PEH duration that was more than three times as
long, 13 h and 4h respectively (Quinn, 2000).
Further investigating the impact of higher intensity exercise and controlling for total work
done (work-rate (w) x time (s)), Jones and colleagues (H. Jones, George, K., Edwards, B.,
Atkinson, G., 2007) compared the PEH response of varying cycling intensities, duration, and total
work done. Jones reported that a short intense (70% VO 2PEAK for 30 min) bout elicited the same
PEH response as a longer lower intensity (40%2PEAK for 50± 8 min) bout matched for equivalent
work indicating that PEH is dependent on total work done and that a shorter more intense bout of
exercise is sufficient to produce a significant PEH response.
Continuing to examine the effect of intensity, a 2010 study by Eicher et al. compared the
PEH responses of 45 pre-hypertensive to Stage I hypertensive men in a crossover design
implementing a control, low (40% VO2peak), moderate (60% VO2peak), and vigorous (100%
VO2peak) intensity bouts of cycling (Eicher, Maresh, Tsongalis, Thompson, & Pescatello, 2010).
During the low and moderate intensity trials, participants performed 30 minutes of continuous
cycling while the vigorous trail consisted of a graded cardiopulmonary exercise stress test. After
completing their designated trail, the participants rested for 45 minutes and then wore ambulatory
BP monitors for the next 24 hours. Eicher reported that after 9 hours, the low and moderate
intensity bouts sBP returned to control levels while the BP response from the vigorous trail
remained below baseline values. The magnitude of the PEH was 2.7 ± 1.6 mm Hg below control
14
values after low (P = .087), 5.4 ± 1.4 mm Hg lower after moderate (P< .001) , and 11.7 ±1.5 mm
Hg less after vigorous (P<.001) (Eicher, et al., 2010). One omission by the authors is that
although In Eicher, et al. sthe higher intensity bout produced significantly lower BP values, one
can reasonably presume that the total duration of the vigorous trail was less than 30 minutes since
it was an exercise stress test.
Duration and PEH.
The primary reason people fail to meet ACSM’s 30 minutes of daily recommended
physical activity is due to a “lack of time” (Booth, Gordon, Carlson, & Hamilton, 2000).
Fortunately, this 30 minutes can be broken up into intervals as short as 10 minutes. This
coincides with most research which use exercise bouts that last from 10 – 60 minutes (Pescatello,
et al., 2004). Wallace’s 2003 clinical review comparing 30 randomized controlled clinical trials
with endurance exercise bouts between 10 – 60 minutes concluded that there does not appear to
be a strong correlation between exercise duration and PEH (Wallace, 2003). It also referred to a
MacDonald study which indicated that PEH can occur from bouts of exercise as short as 10
minutes. In the MacDonald study, the PEH response of 13 normotensive and 8 hypertensive
participants were compared after cycling at 70%VO2max for 10 and 30 minutes. MacDonald
concluded that both durations of exercise were sufficient to produce significant PEH and that the
difference between the two trials was not significant (J. R. MacDonald, MacDougall, & Hogben,
2000). Based on the 2000 MacDonald et. al. study, the duration of the protocols in this study
were expected to be sufficient to produce a significant PEH response.
Resistance Exercise
Far less research has been conducted regarding resistance exercise and PEH responses.
The current ACSM position stand offers no recommendations regarding resistance exercise and
15
of the few articles using randomized controls, none reported any sBP decreases (Pescatello, et al.,
2004).The 1993 ACSM position stand recommends resistance exercise in the form of circuit
training in order to help control BP (ACSM, 1993). A meta-analysis by Kelley & Kelley, as well
as a 2003 clinical review by Wallace, conclude that resistance exercise which implements a
cardiovascular component is more beneficial at BP regulation that standard resistance exercise
alone (Kelley & Kelley, 2000) . According to Wallace, circuit training is characterized by
“lighter loads and more repetitions” while traditional strength training consist of ”higher loads
and fewer repetitions” (Wallace, 2003). A 2010 study comparing exercise intensities in a 6
exercise circuit using moderate (3 sets of 16 repetitions at 43% of 1RM) and light (3 sets of 30
repetitions at 23% of 1RM) intensities while controlling for total work done determined that only
the higher intensity circuit was sufficient enough to cause PEH in non-diabetic normotensive
individuals with peak BP reduction of 11.0± 7.1 mm Hg sBP and 7.7±7.9 mm Hg MAP; (p <
0.05) (Simoes, et al., 2010).
Alternative Modes of Exercise
Despite the American College of Sports Medicine’s thorough compilation of articles in
their 2003 position stand, the primary modes of exercise utilized were walking, jogging, running,
and/or cycling (Pescatello, et al., 2004). Identifying that many alternative forms of exercise exist,
Pescatello suggest that “ any activity that uses large muscle groups, can be maintained
continuously, and is rhythmical and aerobic in nature” should be used as a primary mode to
reduce and control HTN (Pescatello, et al., 2004). Many movement patterns adhere to these
guidelines, including several kettlebell techniques.
16
Kettlebells.
The kettlebell, or Russian “girya” is essentially an iron cannonball with a handle and
dates back as early as 1704. The kettlebell was first used in markets as counterweights until
people started to lift and thrown them around recreationally (Tsatsouline, 2006). Nearly 200
years later, the kettlebell made its first appearance in the United States when it was featured in
“Hercules” magazine in 1913. Within the last decade, kettlebells have become increasingly
popular and are common found in sporting good stores, fitness centers, health magazines, and
even television infomercials. Most of the claims about kettlebells promote them as the ultimate
endurance increasing, muscle building, and fat reducing device are unproven.
Kettlebells are typically swung or lifted using ballistic, powerful, Olympic style lifting
style movements that incorporate the entire body with the primary agonist being the gluteus
maximus and medius, biceps femoris, and quadriceps. These movements incorporate the whole
body and involve significant momentum, torque, and power yet the actual force from many of
these exercises is unknown. A large demographic ranging from amateur weight lifters to
professional girevoy sport competitors uses Kettlebells. Girevoy sport is a competition where
competitors compete to see who can achieve the greatest number swings in a given time in classic
style (Jerk & snatch) or long cycle where the competitors perform as many swings as possible in
10 minutes without rest. This differs from most amateurs who use them solely for exercise and
generally perform several rounds of various exercises in a circuit. Along with a variety of
exercises available, kettlebells also come in a numerous of sizes ranging from 5lbs to 108 lbs.
Currently, there is very little research to support any of the claims about the effectiveness
of kettlebell use. A 2010 study concluded that 12 minutes of self-paced kettlebell swings
produced moderate to high intensity cardiovascular response (65.3 ± 9.8% VO2max and 86.8 ±
17
6.0% HRmax) and were reported to be as effective as running for improving cardiovascular
fitness (Farrar, et al., 2010). The findings from this present study will help determine if kettlebell
exercise is a effective mode of exercise for lowering and controlling blood pressure acutely in
pre-hypertensive and hypertensive Stage I males.
18
Chapter 3
Methods
Research Design
For this study, a randomized pre/post test control group crossover design was
implemented. Each subject underwent pre-treatment BP measurements before participating in a
randomly selected experimental trial consisting of a resting control (CON), 12 minutes of selfpaced two handed kettlebell swings (THS), or a kettlebell circuit (CIR) . Immediately following
the conclusion of the experimental trials, the subjects rested for 20 minutes before having their
HR and BP monitored and recorded from the seated position at 30-minute intervals for next 120
minutes.
Participants
Eight recreationally active, pre-hypertensive and/or stage I hypertensive males with little
to no previous kettlebell experience participated in this study. Their anthropometric data, BP, and
HR values are listed in Table 1. All Participants completed written consent forms and were
classified as low risk according to ACSM guidelines before participating in this study approved
by the California State University, Sacramento’s Human Participants Ethics Committee.
Exclusion criteria for this study included currently taking medication, possessing cardiovascular
abnormalities during rest or exercise, having a systolic/diastolic resting BP ≤ 160 / 90 mmHg,
and/or having orthopedic or other complications that would impair the subject’s ability to
complete the exercise trials.
Table 1
Characteristics of the Participants (Mean ± SD) (n = 8)
Variable
Value
19
Height (cm)
181 ± 5
Weight (kg)
86 ± 15
Age (yrs)
28.5 ± 5.5
SBP (mm Hg)
133 ± 7
DBP (mm Hg)
82 ± 6
Resting HR (bpm)
65 ± 12
Instrumentation
Blood pressure was recorded using a Heine Gamma G7 blood pressure cuff (Herrsching,
Germany). Heart Rate was recorded using a Polar Heart Rate Monitor (Lake Success, NY, USA).
Procedure
Familiarization Period.
At least 48 hours prior to data collection, the subjects completed and signed the informed
consent documentation before having their resting BP values measured in the seated position.
They then completed the Health Assessment questionnaire (Appendix) to determine ACSM risk
stratification. The low risk participants then received hands-on instruction on proper kettlebell
technique using the movements required for both experimental trials. All participants were given
a minimum of 48 hours rest before they returned to the laboratory for subsequent testing.
Experimental Trials.
Pre-experimental procedures include no smoking, caffeine, alcohol, or ergogenic aids
24hrs prior. Strenuous exercise was prohibited 48hrs prior to testing. A 24-hour food log was
kept by participants in order to repeat meals and beverages prior to testing. Three hours prior to
testing, the participants were advised to drink 32oz of water for proper euhydration during testing.
20
All participants underwent three randomly selected experimental trials at the same time
of day to account for any diurnal variations. There were two exercise trials. One trail consisted of
12 minutes of continuous two-handed self-paced swings using a ½ Pood or 35lb kettlebell (THS).
The participants were allowed to place the kettlebell down momentarily if needed but were
informed before the start of the trail to attempt as many swings as possible before time expired.
The second experimental trail utilized a kettlebell circuit (CIR) consisting of 3 sets of 6 exercises
with 10 reps per side (swing, high pull, snatch, clean and press, clean, and reverse lunge) using a
20lb kettlebell. During CIR, participants were allowed to place the kettlebell on the ground
momentarily if needed but were informed before the trail to attempt to complete all repetitions in
as little time as possible. The third experimental trail was the resting control in which
participants sat in an upright-seated position for 20 minutes.
Before experimental trials, the participants rested in a temperature, light, and noise
controlled room for 20 minutes. After which their initial systolic and diastolic blood pressure
were recorded in the seated position. After the subjects’ pre-test resting BP and HR readings
were recorded, they were then informed which randomly assigned trial would complete (CIR,
THS, or CON). At the immediate conclusion of the trail, the participants rested in the seated
position for 20 minutes before BP and HR measurements were recorded for minute 0. Blood
pressure and HR were then recorded afterward every 30 minutes for the next 120 minutes.
Statistical Analysis.
For data analysis, a repeated measures ANOVA with mixed model design was conducted.
Main effects and interaction significance as set at (p ≤ 0.05). Post-Hoc Tukey analysis was used
to determine where statistical differences were located. The independent variables were the
21
various treatments and time while the dependant variables were SBP, DBP, and HR. Statistical
significance level is set at an alpha level of (p < 0.05).
Clinical Significance.
Using the WHO and ISH recommendation, clinical significance was set as any postexercise BP value < 130 mm Hg systolic and < 80 mm Hg diastolic (Whitworth, 2003).
22
Chapter 4
Results
Performance Outcomes
The CIR and THS performance outcomes can be found in Table 2. The maximum and
minimum number of swings during THS was 463 swings and 88 swings respectively. The
shortest time to completion for CIR was 10.9 min while the longest time was 25.1min.
Table 2
The Participants’ Performance Outcomes (Mean ± SD) (n=8)
Trial
Variable
Mean Outcome
THS
Swings completed
273 ± 106
CIR
Time to completion (min)
16.5 ± 4.3
Hemodynamic Response
Systolic Blood Pressure.
Repeated measures ANOVA indicated that both time (F = 8, p = 0.00005) and interaction
of exercise treatment * time (F = 2.3, p = 0.019) were statistically significant. While exercise
treatment alone was not statistically significant (F= 1.9, p = 0.18). The decrease in SBP was
statistically significant from resting values for CIR during minute 30, 60, 90, & 120 and during
minute 0, 30, 60, & 120 for THS. On average, SBP was reduced 7.2 ± 1.2 mm Hg following CIR
and 7.1 ± 1.5 mm Hg following THS. Both trails reduced SBP to clinically significant values (<
130 mm Hg); CIR from minute 0-120 and THS at minute 0, 60, 90, & 120. The values can be
seen in Figure 1. No significant change occurred after CON. The peak magnitude reduction in
SBP for trials CIR and THS occurred at 60min (8.5 ± 1.7 mm Hg) and at 90min (9.3 ± 3.7 mm
Hg) respectively.
23
Only CIR produced a significant decrease in SBP (p < 0.05) compared to CON. The
average decrease during CIR was 6.8 ± 0.98 mm Hg lower than CON from time 0 to 120min.
The peak magnitude difference between CIR and CON was -8.5 ± 1.4mm Hg and occurred at
120min.
24
150
CIR
THS
CON
145
SBP (mmHg)
140
135
*†
130
* †
†*
†
**
125
* †
***
*
**
†
*†
* †
* †
**
120
115
Rest
0
30
60
90
120
TIME (min)
Figure 1. Systolic blood pressure (SBP) before and after exercise.
This figure illustrates that both CIR and THS significantly reduced SBP below resting values
after exercise but only CIR reduced SBP significantly lower than CON.
‡ Minute “0” is represents the first measurement at the conclusion of exercise.
† clinically significant (< 130 mm Hg)
*significantly different from pre-test value (p < 0.05).
** significantly different from CON (p < 0.05).
*** significantly different from THS and CON (p < 0.05). Data are mean (SE).
‡
25
Diastolic Blood Pressure.
Main effects for exercise treatment (F = .12, p = 0.89) and time (F = 1.3, p = 0.28) were
determined. No statistically significant interaction was found between exercise treatment *time
(F = 1.7, p = 1.10). The effect of CIR, THS, and CON on DBP can be seen in Figure 2. While
not statistically significant, the average change in DBP during was -3.62 ± 1.42 mm Hg and 1.00
± 2.75 mm HG following CIR and THS respectfully. Only CIR was able to reduce DBP to
clinically significant values (DBP < 80 mm Hg). Significance occurred at minute 30 (78.8 ± 1.19
mm Hg ) and 60 (79.3 ± 1.19mm Hg ).
26
92
CIR
THS
CON
90
88
DBP (mmHg)
86
84
82
80
†
†
78
76
74
72
Rest
0
‡
30
60
90
120
TIME (min)
Figure 2. Diastolic blood pressure (DBP) before and after exercise.
This figure illustrates that only CIR reduced DBP to clinically significant values at minute 30 and
60.
‡ Minute “0” represents the first measurement at the conclusion of exercise.
† Clinically significant (< 80 mm Hg) Data are mean (SE)
27
Heart Rate Responses
The Main effects for exercise treatment (F = 6.8, p = 0.01) and time (F = 15.5, p =
<0.0001) were analyzed and a significant interaction was found (F = 3.9, p = 0.0004). At time
0min, both CIR and THS trials recorded peak values with HR measurements 36% (23 ± 4.7bpm)
and 33% (21 ± 4.7bpm) above those of CON respectively. No significant difference was found
between CIR, THS, and CON from 60min to 120min. Graphical analysis of the participants HR
response is located in Figure 3.
28
105
CIR
THS
CON
100
95
90
*
**
85
*
**
HR (bpm)
80
75
**
70
65
60
55
50
45
40
Rest
0
‡
30
60
90
120
TIME (min)
Figure 3. Heart Rate (HR) before and after exercise
This figure illustrates that both CIR and THS significantly increased HR compared to Rest and
CON at minute 0 (20 minutes after exercise).
‡ Minute “0” represents the first measurement at the conclusion of exercise.
*significantly different from pre-test value (p < 0.05).
** significantly different from CON (p < 0.05). Data are mean (SE).
29
Table 3
Hemodynamic Responses of Participants (Mean ± SN) (n=8)
a) Systolic blood pressure (mm Hg)
CIR
Rest
131.8 ± 2.1
0 min
126.3 ± 2.7†
30 min
124.0 ± 2.4*†
60 min
123.3 ± 1.7*†
90 min
125.5 ± 2.1*†
120 min
124.0 ± 1.4*†
THS
136.3 ± 2.8
129.8 ± 4.2*†
131.0 ± 3.4
129.0 ± 3.1*†
127.0 ± 3.7*†
129.3 ± 3.6*†
CON
132.5 ± 2.1
133.3 ± 2.1
130.5 ± 2.2
129.8 ± 2.6
130.8 ± 2.4
132.5 ± 1.8
b) Diastolic blood pressure (mm Hg)
CIR
Rest
84.0 ± 1.7
0 min
82.3 ± 1.4
30 min
78.8 ± 1.2†
60 min
79.3 ± 1.2†
90 min
81.5 ± 1.5
120 min
80.0 ± 1.9
THS
81.3 ± 2.2
80.8 ± 2.9
81.8 ± 3.2
81.8 ± 3.1
82.3 ± 2.6
83.3 ± 2.0
CON
80.3 ± 2.4
80.8 ± 2.0
80.0 ± 2.0
81.3 ± 2.2
83.3 ± 1.9
83.0 ± 1.7
THS
64.3 ± 5.5
84.7 ± 4.7*
71.1 ± 5.6
66.4 ± 4.9
63.9 ± 5.6
63.8 ± 3.9
CON
63.7 ± 4.4
64.3 ± 3.4
61.3 ± 3.4
61.3 ± 4.5
59.4 ± 3.8
61.3 ± 4.8
c) Heart rate (bpm)
Rest
0 min
30 min
60 min
90 min
120 min
CIR
69.1 ± 4.6
86.9 ± 4.7*
74.0 ± 4.3
71.4 ± 3.2
63.7 ± 4.4
64.3 ± 4.9
*Significantly different from Rest (p < 0.05)
†Clinically significant (SBP/DBP < 130/80 mm Hg)
30
Chapter 5
Discussion
Significant Outcomes
The main findings from this study are as follows. First, both kettlebell routines tested in
this study were able to elicit a decrease in SBP post-exercise that was clinically (SBP < 130 mm
Hg) and statistically significant. Second, there was a trend for CIR to reduce DBP to clinically
normal values (DBP < 80mm Hg). Third, THS was unable to reduce DBP to clinically or
statistically significant values.
Our hypothesis regarding SBP was correct as the SBP reductions were clinically
significant from pre-test values for CIR from minute 0-120 and at minute 0, 60, 90, & 120 for
THS. Compared to pre-test values, the decreases in SBP were statistically significant for CIR at
minute 30, 60, 90, & 120 and THS at minute 0, 30, 60, & 120. The average magnitude of
decrease of CIR (7.2 ± 1.2 mmHg) and THS (7.1 ± 1.5 mmHg) was similar to previous research
utilizing endurance (Pescatello, et al., 2004; Whelton, Chin, Xin, & He, 2002) or resistance
training (Kelley & Kelley, 2000; Wallace, 2003) in order to obtain PEH. Despite both trials
lowering SBP, only the decrease during CIR was statistically significant compared to control at
minute 0, 30, 60, & 120.
Our hypothesis concerning DBP was partially correct given that only CIR decreased DBP
to clinically significant values while THS did not. The decrease in DBP at minute 30 and 60
from CIR was clinically significant. While CIR reduced DBP post exercise (average value 3.62 ±
1.42mm Hg), was not statistically significant due to the small sample size (n=8) involved in this
study. The results from this study are similar to previous research where physically fit
individuals performed resistance training routines and only SBP decreased significantly post-
31
exercise (Anunciacao, 2011; Boroujerdi, Rahimi, & Noori, 2009; Fisher, 2001). One possible
explanation for the lack of DBP is because participants were seated during post-exercise BP
measurements. Sitting down compared to lying supine during post-exercise measurements causes
an increase in systemic vascular resistance and also DBP (AL Mark, 1996; de Tarso Veras
Farinatti, Nakamura, & Polito, 2009). A secondary explanation for the small DBP decrease is
due to the reduced pre-test values (82 ± 6 mm Hg). Several studies have concluded that the
magnitude of PEH is depended on the severity of the BP before exercise (Pescatello, et al., 2004;
Sharman & Stowasser, 2009).
Mechanism
After the bouts of exercise, HR increased significantly at minute 0 for THS and at minute
0 and 30 for CIR. Increases in HR have been shown to be an indicator of increased sympathetic
nervous system activity (SNA) (J. R. MacDonald, 2002). In similar studies using both resistance
and endurance exercise, an increase in HR was accompanied by an increase in SNA and systemic
vascular resistance (SVR); yet stoke volume (SV) and cardiac output (CO) both decreased
causing PEH (Rezk, Marrache, Tinucci, Mion, & Forjaz, 2006; Teixeira, Ritti-Dias, Tinucci,
Mion Júnior, & Forjaz, 2011). This decrease in SV causes a reduction in venus return and thus
reduces CO and produces PEH (Crivaldo Gomes Cardoso, 2010; Rezk, et al., 2006; Teixeira, et
al., 2011; Veloso et al., 2010). A reduction in SV after exercise is not the only mechanism
responsible for PEH because SV levels have been reported to return to normal levels after
exercise despite the BP remaining below baseline indicating that a secondary mechanism exist (J.
R. MacDonald, 2002).
It is widely accepted that decrease in total peripheral resistance (TPR) and vascular
resistance occurs after exercise and cause PEH. The reductions in TPR and vascular resistance is
32
due to the release of local vasodilators such as La-, NO, histamine, adenosine, and ATP. No
current consensus exist regarding the individual or cumulative role these substances play in
causing PEH (J. R. MacDonald, 2002; Moraes et al., 2007; Pescatello, et al., 2004; Veloso, et al.,
2010). Future research using kettlebells should investigate the SNA, SV, and CO response after
exercise in addition to the role that various vasodilators have on PEH.
Cardiac and skeletal muscles’ afferent nerve activity also helps contribute to causing a
post-exercise hypotensive response (Chen & Bonham, 2010; Moraes, et al., 2007; Pescatello, et
al., 2004). More specifically, the kallikren-kinin system and the neromodulator GABA have been
reported to alter baroreflex sensitivity during and after exercise resulting in PEH (Chen &
Bonham, 2010; J. R. MacDonald, 2002). The varying roles of central and peripheral nervous
system responses in regard to PEH was beyond the scope of this study and should be further
investigated in the future.
Relevance of Findings
Kettlebells have existed for nearly 300 years but have just recently gained mainstream
popularity and recognition from the scientific community (Farrar, et al., 2010; Tsatsouline, 2006).
The results from this study indicate that the use of kettlebells can have significant cardiovascular
benefits including the acute reduction blood pressure to clinically significant levels. The kettlebell
routines prescribed in this study only represent a small sample of the numerous possible
movement and routine combinations available. Similarly, current research has only examined
the BP response of a handful of movement patterns and exercises (running, cycling, standard
weight lifting) negating such things as dance, the martial arts, and the effects of other tools
utilized by the physical sub-culture (kettlebells, sandbags, tires, ropes, jori clubbells, etc.). Future
33
research should consider examining the physiological effects and potential cardiovascular
benefits of alternative movement patterns in hopes of staying relevant not only within the
scientific community, but also within the fitness and within clinical communities as well.
Future Research
This Study examined the BP and HR response for 120 minutes post exercise. The results
from his study indicate that kettlebell exercise is beneficial for acute BP regulation however ,
many questions remain and should be considered for future research such as the 24 hour BP
response and the chronic BP response to kettlebell exercise.
The nature of kettlebell swings contains a strong eccentric component. While the
eccentric position of exercise strongly contributes to delayed onset muscle soreness, resent
research has reported that as little as 30 minutes of eccentric exercise per week for 8 weeks can
increase fat oxidation, increase insulin resistance, and improve one’s blood lipid
profile(Paschalis et al., 2010). The movements involved in this current study have a strong
eccentric component so investigating the chronic physiological adaptations as well as the forces
involved in KB swings should also be a consideration for future research.
During this current study, participants performed upwards of 400 swings without rest indicating
that the intensity (based on 1-RM) was far less than those found in other resistance exercise
studies (Pescatello, et al., 2004; Wallace, 2003). The high swing rate of this study utilized more
power and less force or strength. This indicates that the protocols used in this study might be
better classified as endurance exercise as opposed to resistance. Future research should consider
a way to determine both the cardiovascular and resistance intensity of kettlebell exercise in order
ensure the uniformity in total work done by participants in future research.
34
Conclusion
Both kettlebell routines were able to produce a statistically and clinically significant PEH
response in SBP but only the circuit trial was able to reduce DBP to clinically significant values.
The findings of this study can only be limited to recreationally active males (age 28.5 ± 5.5) who
are Stage I hypertensive or pre-hypertensive. Nonetheless, the results from this study indicate
that kettlebells can be used as an effective mode of exercise for regulating blood pressure in those
who are pre-hypertensive or who have HTN. Future research should consider examining the
physiological mechanism and response to kettlebell training but acutely and chronically.
35
APPENDIX A
Consent to Participate
36
Consent to Participate in Research
(purpose of the research) You are being asked to participate in research which will be
conducted by Dr. Roberto Quintana, a professor of Kinesiology at California State University,
Sacramento. The purpose of the study is to determine if two popular kettlebell routines are
sufficient in eliciting a decrease in blood pressure post exercise.
(research procedures) After completing a health history questionnaire to assess your risk
factors for cardiovascular disease, your resting blood pressure will be recorded and if you meet
the requirements for this study (BP >120/80 mm Hg and <150/100 mm Hg) , you will be
enrolled. Afterwards, you will receive instruction on proper kettlebell form and technique. You
will then return to lab and be asked to perform a randomly selected trial consisting of either
kettlebell exercise or a resting control. Immediately following the exercise or control, your blood
pressure will be monitored for 120 minutes in a temperature, noise, and lighting controlled room.
For some of these tests, you will wear a heart rate monitor to measure your heart rate. The tests
will be conducted on three separate days in the exercise physiology laboratory at Sacramento
State and will require up to 3 hours each day.
(risks) Any exercise involves a risk of possible injury or even heart attack, but these risks are
considered very small. The risk for heart attack is estimated to be less than 0.04%
for people who are suspected to have cardiovascular disease, and substantially less than that for
people who are in good health, have few or no risk factors for cardiovascular disease, and have no
symptoms of cardiovascular disease. It is essential for you to provide accurate information on the
health history questionnaire to be sure that you fall in this low risk category. Muscular strength
testing involves a risk of muscle strain. You will experience increased blood pressure, rapid
breathing, increased heart rate, sweating, muscular discomfort, and fatigue during the exercise
portion for this study. It is also possible that you will experience an alteration in heart rhythm. If
you experience any chest pain, tightness, or other abnormal discomfort during the testing
procedures, you should notify the researcher immediately. All of the researchers are trained in
CPR/AED procedures if the need should arise.
(benefits) The exercise tests may provide you with information about your current state of
health and physical fitness. The information may also be helpful in developing or altering an
exercise program to enhance your physical fitness and control your blood pressure.
(confidentiality) All results obtained in this study will be confidential. Your individual
performance will not be reported, only the results of all participants as a group. Information you
provide on the consent form and the health history questionnaire will be stored separately from
data for the exercise tests; the exercise test data will contain no personal information about you.
(compensation) You will one complementary personal training session at Body Tribe
Fitness as compensation for participating in this research. In the event of an emergency, initial
medical treatment would be available at the Sacramento Student Health Center. However, if you
were to require any other medical care as a result of participating in this research, you would need
to contact your personal physician at your own expense.
37
(contact information) If you have any questions about this research, you may contact
Dr. Roberto Quintana at (916) 278-4495 or send e-mail to quintana@csus.edu.
Your participation in this research is entirely voluntary. You are free to decide not to
participate, or to decide at a later time to stop participating. The researcher may also end your
participation at any time. By signing below, you are saying that you understand the risks
involved in this research and agree to participate in it.
___________________________
Signature of Participant
________________________________
Date
___________________________
Signature of Witness
________________________________
Date
38
APPENDIX B
Pre-Test Instructions
39
Pre-Test Instructions
You have qualified to be a participant in the study describing the acute BP response of two
popular kettlebell routines. Below you’ll find a list of pre-test restrictions and
recommendations. The requirements and restrictions must be followed prior to testing while
the recommendations will help insure that your participation in this study goes smoothly.
Requirements:
Must be completed before testing

Drink 500 mL (32oz) of water 3hrs prior to test
Restrictions:
Avoid the following for 48 hours prior to testing.

Exercise or strenuous physical activity

Alcohol

Tobacco

Caffeine

Erogenic Aids (ie. Energy drinks, fat burners, creatine, etc.)
Recommendations:
Not necessary but highly recommended.

Get an adequate amount of sleep the night before

Bring exercise clothes & a water bottle

Bring reading materials and/or a laptop to keep you busy in between
measurements
Please plan to stay for approximately 3 hours. I look forward to working with you. If you have
any questions feel free to contact John Martin (630) 222-7766.
APPENDIX C
Participation Screening Questionnaire
40
AHA/ACSM Health/Fitness Facility Pre-participation Screening Questionnaire
Please mark each statement that applies to your health status
---------------------------------------------------------------------------------------------------------History
You have had:
Heart surgery
If you marked any of these
statements in this section, consult
your physician or other appropriate
health care provider before
engaging in exercise. You may
need to use a facility with a
medically qualified staff.
41
Symptoms
-injury,
or are currently taking medications for an injury)
42
Other health issues
You have burning/cramping in your lower legs when walking short distances
Cardiovascular risk factors
than 45 years
If you marked two or more of
the statements in this section,
you should consult your
physician or other appropriate
heath care provider before
engaging in exercise. You
might benefit from using a
facility with a professionally
qualified exercise staff to
guide your exercise program.
cholesterol level
age 55 (father or brother) or age 65 (mother or sister)
on at least 3 days per week)..
----------------------------------------------------------------------------------------------------------
You should be able to exercise safely without consulting your physician or other
appropriate health care provider in a self-guided program or almost any facility that
meets your exercise program needs.
_______________________________________________________________________
Modified from American College of Sports Medicine and American Heart Association.
ACSM/AHA Joint Position Statement: Recommendations for cardiovascular screening, staffing,
and emergency policies at health/fitness facilities. Medicine and Science in Sports and Exercise
1998: 1018.
43
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