Strength
We will divide strength into five categories.
These five types of strength are:
Maximum strength
Static strength
Explosive/elastic strength
Dynamic strength
Strength endurance
Maximum strength
Definition – maximum force that a muscle can exert in a single
voluntary contraction.
Tests
- 1 Rep max –The performer lifts the max weight that they can
just once, Trial and error is required, so plenty of rest is
needed in between each attempt.
- Hand grip/leg dynomometer - The performer squeezes the
dynamometer whilst lowering it from shoulder height to the
side. Three attempts (with rests). Highest score recorded.
Static strength
Definition – Force exerted by the muscle while the muscle length
remains constant/static. An isometric contraction – where a force is
applied but the muscle length remains the same.
Test
No generic test as the strength will vary depending on the angle that
the joint is held at.
Explosive /elastic strength
Definition – The application of strength and speed – Power. The
ability to overcome a resistance with a high speed of contraction.
Eccentric followed by a concentric contraction (muscle lengthens
and then shortens – stretch reflex).
Tests
Vertical jump test- The performer stands and marks against a wall
his full reach. They then crouch and jump, marking the wall as high
as they can. The measurement between the two marks is taken. This
measurement is then compared against national norms.
Standing broad jump- The performer stands, feet parallel behind a
line. They jump as far forward as they can. A measurement is taken
from the line to the back of the closest foot to the line. This result
is then compared against national norms.
Dynamic strength
Definition – The ability to apply a large force repeatedly over a
sustained period of time
Test
Wingate Cycle Test – Performer (after a warm up) pedals ‘all out’
for 30 seconds whilst seated on a cycle ergometer. The test
measures peak anaerobic power, the rate of decline (fatigue), and
the average power output during the test.
Muscular endurance
Definition – Ability for muscle to perform repeated contractions
or sustain (hold) a single one.
Test
There are a number of localised tests for specific muscles/muscle
groups.
NCF abdominal curl test – Similar to the bleep test. The performer
carries out a series of sit ups in time with the bleep. The test is
progressive. At the end of each stage the bleep becomes closer
together. The test ends when the performer fails to keep up with
the bleep. The stage and number of sit ups is recorded and
compared to national norms.
Another popular test is the press up test, which tests the
endurance of the arms and shoulder.
The three main types of strength found in sporting application and
health related activities would be:
Explosive/Elastic and Dynamic strength. – both represent anaerobic
strength.
Strength endurance – represents aerobic strength.
Factors affecting strength
Muscle composition
The greater the following, the greater the force the muscle can
generate.
- Percentage of fast twitch muscle fibre
- Cross-sectional area of muscle
- Size of muscle
Gender
Generally males are stronger than females. This is as a result of:
- Generally have less cross-sectional area
- Generally have smaller muscle size
- Having less testosterone than males
Age
Females strength peaks between 16-25 years, with males peaking
between 20-30 years.
Greatest gains are made between 20-30 as testosterone levels are
at their peak.
Strength generally decreases with age as testosterone levels
decrease.
This leads to less muscle mass, and a less efficient neuromuscular
system (ability to efficiently coordinate muscle contraction).
Physical Inactivity
Muscle atrophy (decrease in muscle size) will occur after approx. 48
hours of inactivity.
This would mean the loss of any strength gain from training
(reversibility).
Strength training
Specific strength training will bring specific strength gains such as
hypertrophy (muscle growth) and its associated strength gain, and
prevent atrophy from inactivity. We will look in more detail at the
benefits when looking at the adaptations later.
Types of strength training
Multi-gym
Free weights
Interval/circuit
Plyometrics
See p433-437 for details of these
When answering a strength training question there are some key
words and terms that you will need include.
Reps – the number of times that an exercise or move is repeated.
This will vary depending on which strength is being developed.
Set – a number of reps make up a set. There is a period of rest
before the next set begins. E.g. ten reps may make one set. Typically
there would be between 3 – 5 sets.
Training load/resistance – Typically this is the weight that is being
lifted. E.g. Bench press 3 sets of 10 reps of 80kg.
Recovery – the rest period between reps and sets will vary
depending on the type of strength required. Rest between training
sessions needs to be sufficient to allow recovery and adaptations to
occur.
1 rep max – this is the maximum load/resistance that can be lifted
just once. The relevance to training comes from your training load
being a % of your 1 rep max score. Training will require the training
load to be between 50% and 80% of 1 rep max. Below 50% and there
will be no training adaptation. Above 80% and there is a risk of
injury.
Maximum strength will require a high training load/resistance with a
low number of reps.
Strength endurance will require a low training load/resistance with a
high number of reps.
Power requires moderate training load/resistance so that a higher
speed of movement can be achieved.
See previous notes for more details on reps/sets/loads.
Other considerations when strength training
Moderation – general strength conditioning should be done before
specific muscle groups to prevent damage from overtraining.
Exercise large muscle groups before small ones, as the smaller ones
may act as stabilisers for the larger ones. If they are fatigued this
could affect the quality and safety of the larger movement.
Periodisation – Ensure that the training is appropriate for the time
of the training year. This will prevent overtraining and its associated
injury risk and decline in performance.
Energy systems and food fuels
Elastic/explosive strength – ATP/PC system –ATP/PC (fuel)
Dynamic strength – Lactic acid system – Glycogen/glucose (fuel)
Strength endurance – Aerobic system – glycogen/glucose/FFAs
(fats)
Adaptations to strength training
Strength training can produce 25-10 % improvements in strength
over a period of between 3 and 6 months.
There is a great increase in strength in the early stages of training
without hypertrophy taking place.
The reason for this gain is the neural adaptations that take place in
the first 2 weeks of training.
Neural adaptations
- Reduction in inhibition of movement receptors (golgi tendon
organs-proprioreceptors)/antagonist muscles which act as
contraction limiters. This inhibition of allows a greater stretch
and therefore a greater force of contraction of the agonist
muscle.
- Increased recruitment of fast twitch fibres.
- More motor units recruited.
- Improved co-ordination of motor units.
Physiology adaptations
Skeletal muscle
- Hypertrophy – increase in muscle size(mainly fast twitch).
- Hyperplasia – increase number of muscle fibres (splitting of
muscle fibres)
- Increase in size/number of contractile proteins (width of
actin/myosin)
- Increase in actin/myosin cross bridges (to contract muscle,
actin and myosin pull on each other with cross bridges - more
cross bridges, more strength)
- Increased number of mitochondria (Aerobic adaptation)
- Increased number of myoglobin (aerobic adaptation)
- Capillarisation -increase in capillary density within muscle
(aerobic adaptation)
Aerobic adaptations will occur as a result of strength endurance
training.
Metabolic
- Increase in ATP/PC stores
- Increase in lactic acid buffering (tolerance of lactic acid build
up in fast twitch fibres)
- Increase in efficiency of lactic acid removal.
- Increase in enzyme action (GPP and PFK).
- Result is an increase in the PC/lactic acid threshold/anaerobic
threshold/delay in OBLA and subsequent fatigue/increased
recovery of ATP/PC system.
Therefore a potential for increase in intensity and time of
performance.
Other adaptations
- Increase in strength of connective tissue – tendons,
ligaments and bones (increased calcium produced).
- Social/psychological benefits- increase in muscle mass
perceived as being attractive, which can have a positive effect
on self-esteem in both a sporting and lifestyle context
Practice dividing adaptations into aerobic and anaerobic.
Remember some of the benefits of strength endurance training
come from the improvements in the cardiovascular and respiratory
systems.
Cardiovascular adaptations to pure strength training (weight
lifters and body builders).
Hypertrophy of the heart
Increased blood pressure
Decrease in volume of left ventricle
These adaptations that result from low reps/high number of
sets/high weights performed slowly (involving a high proportion of
isometric contraction), are largely negative.
( see p440 for more detail)
Test yourself
Can you:
- Define the types of strength.
- Explain the factors that affect strength.
- Describe the tests that are used to evaluate the different
types of strength.
- Explain and describe the different training methods used to
develop strength.
- Describe the energy systems and food fuels used during the
different types of strength.
- Describe the adaptations hat occur after a period of strength
training (aerobic and anaerobic).