PT 153: Therapeutic Exercise 2 STRENGTHENING EXERCISE AILA NICA J. BANDONG, PTRP Instructor Department of Physical Therapy UP-College of Allied Medical Professions Learning Objectives At the end of the lecture, the students should be able to: • identify the factors affecting tension generation in muscles. • discuss the principles of resistance exercise aimed at increasing strength. • discuss the determinants of resistance exercise. • differentiate the various forms of resistance exercise. • identify guidelines to providing resistance exercise for various age groups. • discuss considerations for designing resistance exercise for children. • enumerate precautions and contraindications to treatment using resistance exercise. Power Strength Endurance MUSCLE PERFORMANCE STRENGTH • Ability of contractile tissue to produce tension and a resultant force based on the demands placed upon it • Greatest measureable force that can be exerted to overcome resistance in one maximum effort STRENGTH TRAINING • A systematic procedure of a muscle or muscle group lifting, lowering, or controlling resistance for a particular number of repetitions or over a short period of time Principles of Resistance Exercise Overload SAID Reversibility Overload Principle • If improvements in muscle performance is desired, the muscle must be challenged to perform at a level greater than that to which it is accustomed to • Progressive loading of muscle through increasing intensity or volume SAID Principle S pecific A daptation to I mposed D emands • A framework of specificity is a necessary foundation on which exercise programs should be built Reversibility Principle • Unless training-induced improvements are regularly used or resistance exercises are maintained, adaptive changes are only temporary • Detraining begins at one to two weeks after cessation of exercise Effect of Strength Training Increase in the maximum force-producing capacity of muscle due to physiological adaptations of the body to resistance exercise Determinants of Resistance Exercise • • • • • • Alignment Stabilization Intensity Volume Exercise order Frequency • • • • • • Rest interval Duration Mode of exercise Velocity Periodization Integration to functional activities Alignment • Muscle Action – The direction of movement of a limb or segment of the body replicates the action of the muscle or muscle group being strengthened • Gravity – Muscle being strengthened should act against the resistance of gravity and additional force provided by a device/equipment Stabilization • Refers to holding down a body segment or keeping the segment/body steady during performance of exercise – External – Internal Intensity • aka training load, exercise load • Amount of resistance imposed on the contracting during each repetition • Should follow the overload principle – Intensity is greater than the usual load carried and progressively and gradually increased Intensity: Sub-maximal Loading Indications • • • • • • • At the beginning of exercise During early stage of soft tissue healing After immobilization Children and older adults Improvement of muscular endurance During warm up and cool down During slow-velocity isokinetic training Intensity: Maximal Loading Indications • Goal to increase strength and power and muscle size • Healthy individuals in the advanced phase of a rehab program • Conditioning program for the well population • Training for competitive weight lifting and body building Intensity: Determining the Amount of Load • Repetition Maximum • Other methods – Cable tensiometry – Dynamometry (hand-held, isokinetic) – Percentage body weight Intensity: Calculating Initial Load • As a factor of repetition maximum – Sedentary individuals/untrained individuals/children/elderly: 30% to 40% of 1RM – Patients with significant strength impairments: 30% to 50% of 1RM – Highly trained individuals: 80% to 95% of 1RM Intensity: Calculating Initial Load • As a factor of body weight (percentage) – Universal bench press: 30% body weight – Universal leg extension: 20% body weight – Universal leg curl: 10-15% body weight – Universal leg press: 50% body weight Volume • Summation of the total number of repetitions and sets of a particular exercise during a single session • Inverse relationship between intensity and volume of resistance exercise • Repetitions vs. Sets Volume: Training to Improve Strength • Exercise protocols – De Lorme – Oxford – DAPRE • Use an exercise load that cause fatigue after 6 to 12 repetitions for two to three sets; if fatigue no longer occurs, increase level of resistance Exercise Order • Refers to the sequence in which muscle groups are exercised during a session – Large muscle groups before small, isolated muscles – Multi-joint muscles before single-joint muscles – Higher intensity exercise before lower intensity (following an appropriate warm up) Frequency • Number of sessions performed in a day or in a week • Dependent on the following factors: – – – – – – Intensity Volume Patient’s goals Health status Previous participation in resistance exercise Response to training Frequency: Guidelines • Low intensity, low volume: short sessions performed daily or several times daily • As intensity and volume increases: frequency decreases to every other day or up to five sessions weekly • Frequency of two times weekly for maintenance programs Frequency: Guidelines • Prepubescent children and very old: frequency is two to three times/sessions weekly • Highly-trained athletes: high intensity and high volume performed 6 days per week Rest Interval • aka recovery period • Rest between sets and exercise sessions • Dependent on the intensity and volume of exercise as well as status • Active recovery is more efficient than passive recovery to neutralize effects of fatigue • Decreasing rest interval between bouts and sessions as strategy to increase dosage Duration • Total number of weeks or months that the resistance exercise program is performed – For hypertrophy or increase in vascularization to occur, at least 6 to 12 weeks of resistance training is needed – Depending on the nature of impairment, the training program may last from about a month or two to lifetime training to maintain optimal function Mode of Exercise • The form or type of exercise or the manner in which the exercise is carried out • Classification: – – – – – Forms of exercise Type of muscle contraction Weight bearing vs Non-weight bearing Energy system used Short arc vs Full arc exercise Mode of Exercise: Forms of Exercise • Manual and mechanical resistance • Constant or variable load through free weights/weigh machines • Accommodating resistance using isokinetic dynamometer • Body weight as resistance Mode of Exercise: Type of Muscle Contraction • Isometric or dynamic muscle contraction – Dynamic can be performed either CONCENTRICALLY or ECCENTRICALLY • Isokinetic contraction: speed of limb movement is held constant by a device/equipment (controlled dynamic contraction) Mode of Exercise: Weight-bearing vs Nonweight-bearing • Nonweight-bearing with distal extremity moving: open-chain exercise • Weight bearing with body moving over a fixed distal segment/extremity: closedchain exercise Mode of Exercise: Energy Systems • Anaerobic exercise: high-intensity exercise carried out for a limited number of repetitions and utilized as part of a strengthening exercise program Mode of Exercise: Short-arc vs Full-arc • Full-arc: develop strength throughout the entire range of motion • Short-arc: utilized to avoid painful motion or a part of the range where the joint is unstable and to protect healing tissues following injury Velocity • Refers to the speed with which an exercise is performed • Varies with concentric and eccentric muscle contraction Velocity: Implication to Resistance Training • With free weights, slow to medium speed/velocity of movement is safer and more effective as patient can maintain control of movement • Speed-specific training • Plyometric training • Isokinetic training Periodization • aka periodized training • A method of designing a systematic variation in exercise intensity and volume at regular intervals over a specified period of time • Used to limit overtraining and psychologic staleness • Designed for preparing athletes for competition Integration to Function • Balance of stability and active mobility – Exercise program should address both static and dynamic strength of the trunk and extremitites • Balance of strength, power, and endurance • Progression of movement patterns – Isolated strengthening, combined patterns, task-oriented movement patterns Manual Resistance Exercise • A form of active-resistive exercise in which resistance is applied by the therapist to a dynamic or a static muscle contraction – Throughout the available ROM – Various planes of motion – Isolated muscle contraction or group of muscles Mechanical Resistance Exercise • aka weight training, load-resisting exercise • Any form of exercise in which the resistance is applied by an equipment Equipments Used • • • • • • Free weights Elastic resistance Weight-pulley system Closed-chain training equipments Reciprocal exercise equipment Isokinetic training equipment Exercise Regimens • • • • Progressive Resistive Exercise Circuit Weight Training Plyometric Training Isokinetic Regimens Exercise Regimens: Progressive Resistive Exercise • Dynamic resistance training in which a constant external load is applied to the contracting muscle and incrementally increased • Use of RM as basis for determining and progressing resistance DeLorme Oxford Determination of 10 RM Determination of 10 RM 10 reps @ 50% of 10 RM 10 reps @100% of 10 RM 10 reps @ 75% of 10 RM 10 reps @ 75% of 10 RM 10 reps @ 100% of 10 RM 10 reps @ 50% of 10 RM SETS REPETITIONS AMOUNT OF RESISTANCE 1 2 10 6 50% of 6 RM 3 Maximum possible Maximum possible 100% 0f 6 RM 4 75% of 6 RM 100% of adjusted working weight Adjusted working weight (DAPRE) Repetitions in Set 3 Set 4 Next Exercise Session 0-2 5-10 lbs 5-10 lbs 3-4 0-5 lbs 5-6 Same weight Same weight 5-10 lbs 7-10 5-10 lbs 5-15 lbs 11 or more 10-15 lbs 10-20 lbs Exercise Regimens: Circuit Weight Training • Pre-established sequence of continuous exercises are performed in succession at individual exercise stations that target a variety of major muscle groups (8-12) as an aspect of total body conditioning – Minimum amount of rest interval between stations (15-20 seconds) • Alternate among upper/lower extremity and trunk musculature Exercise Regimens: Circuit Weight Training • • • • • Bench press Leg press or squats Sit-ups Upright rowing Hamstring curls • • • • • Trunk extension Shoulder press Heel raises Push-ups Leg lifts or lowering Exercise Regimens: Plyometric Training • aka plyometrics, stretch-shortening drills, reactive neuromuscular training • A system of high-velocity resistance training characterized by a rapid eccentric contraction followed by a rapid shortening contraction of the same muscle Exercise Regimens: Plyometric Training • Three phases – Stretch cycle: eccentric loading phase – Amortization phase: period of time between stretch and shortening cycles – Shortening cycle : concentric phase • Sources of resistance: body weight, external load Exercise Regimens: Plyometric Training • Appropriate only in the later stages of rehabilitation of active individuals requiring high level of physical performance in high-demand activities • CRITEARIA for Plyometric Training: – 80 to 85% level of strength – 90 to 95% ROM Exercise Regimens: Isokinetic Regimens • Velocity Spectrum Rehabilitation – Performance of exercises at various velocities • Limb is accelerated at the predetermined speed/velocity then resistance is applied by the torque arm of the dynamometer through a small portion of the ROM • Performed without pain Exercise Regimens: Isokinetic Regimens • Training velocities – Medium angular velocity: 60/90-180 degrees/sec – Fast angular velocity: 180-360 degrees/sec – Increments of 30 degrees/sec • Sub-maximal intensity/effort for a brief warm-up period maximal intensity Exercise Regimens: Isokinetic Regimens • One or two sets of 8-10 upto 20 repetitions of concentric contractions of antagonist muscle groups at multiple velocities • Rest of 15-20 seconds between sets and 60 seconds rest period between exercise speeds • Maximum frequency of 3x/week Exercise Regimens: Isokinetic Regimens • Progression – – – – Submaximal maximal Intermediate and slow speed fast Short arc full arc exercises Concentric eccentric • Eccentric performed to further challenge the individual muscle groups when strength deficits persist Exercise Regimens: Isokinetic Regimens Eccentric Isokinetic Training Isometric Exercise • aka static exercise • Muscle contracts and produces force without change in length of the muscle and without visible joint motion • Sources of resistance: – Manually, weights, maintaining a position against body weight, pushing/pulling an immovable object Rationale and Indications • Prevent or minimize muscle atrophy when joint motion is not possible due to external immobilization • Activate muscles to begin to re-establish control and protect healing tissues following soft tissue injury or surgery • Develop postural or joint stability • Improve muscle strength if dynamic exercise could cause joint pain and compromise joint integrity • Develop static muscle strength st particular points in the ROM needed for specific task-related needs Types of Isometric Exercise • Muscle-setting exercise • Stabilization exercise • Multiple-angle isometrics Muscle-setting Exercise • Low intensity isometric exercise performed against little to no resistance • Benefits: – Promotes relaxation and circulation – Decrease muscle pain and spasm after injury to soft tissues during acute stage of healing – Maintains mobility between muscle fibers during healing – Retard atrophy during immobilization Stabilization Exercise • Benefits: – Develop sub-maximal but sustained level of co-contraction – Reduce instabililty – Enhance joint or postural stabililty • Variations: – Rhythmic stabilization – Alternating isometrics – Dynamic stabilization Multiple-angle Isometrics • A system of isometric exercise where resistance is applied manually or mechanically at multiple joint positions within the available ROM • Goals: – Improve strength throughout ROM but dynamic resistive exercise causes pain or not advised Considerations • Intensity: dependent on joint position • Duration: held for 6-10 seconds to allow for peak tension to develop and for metabolic changes to occur • Repetitive Contractions: decreases muscle cramping and increases effectiveness of the regimen • Joint Angle: resistance at 4-6 points in the available ROM Limitations • Improvements occur only at or closely adjacent to the training angle • Little or no carry-over of strength gains to dynamic exercise • Not as effective for developing muscle endurance as resisted dynamic exercise Guidelines: Healthy Adults (<60 y/o) • Perform warm-up activities followed by flexibility exercises prior to resistance training • For total body muscular fitness: perform dynamic exercises that target approx 8-10 muscle groups of the U/LE • Balance flexion-dominant (pulling) with extension-dominant (pushing) exercises • Move through the full, available, and pain-free ROM • Include both concentric (lifting) and eccentric(lowering) muscle actions Guidelines: Healthy Adults (<60 y/o) • Use moderate-intensity exercises at least 8-12 repetitions per set • Perform 1-3 sets of each exercise • Include rest periods of 30-60 seconds between sets • Frequency of 2-3 times per week • Use slow to moderate speeds of movement • Use rhythmic, controlled, non-ballistic movements • Cool down after the completion of exercise Guidelines: Healthy Adults (<60 y/o) • Exercises should not interfere with breathing: avoid valsalva maneuver • Increase intensity gradually (5% increments) as progression • Train with a partner for feedback and assistance, if possible • When re-initiating weight training after a period of exercise cessation (>1-2 weeks), reduce resistance and volume of exercise Guidelines: Older Adults (>60 y/o) • Perform at least 5-10 minutes of warm-up activities before each session of resistance exercises • Low to moderate levels at 10-12 repetitions for 6-8 weeks • Perform resistance training 2-3x weekly, allowing 48-hour rest periods between sessions • Avoid flexion-dominant resistance training that could emphasize postural changes Guidelines: Older Adults (>60 y/o) • Low intensity exercise to minimize excessive stress on the joints • Resistance training should be initiated with close supervision and minimal resistance • Maintain functional ROM • Monitor vital signs, especially when the program is progressed • After a 1 to 2-week layoff, reduce the intensity of weight training by 50% Resistance Exercise Among Pre-adolescents (Blimkie, C., 1993) • Pre-adolescence: period between pre- and early puberty until 11 y/o (girls) and 13 y/o (boys) • Remained to be a debatable issue among the lay and scientific community • Positive correlation of strength gains and resistance training can not be generalized due to methodological flaws and limited literature Physiologic Adaptations VARIABLES Max voluntary strength Evoked twitch force Muscle cross-sectional area Neuromuscular adaptation Motor coordination Body mass Lean body mass TRAINING DETRAINING Definite increase Likely decrease Likely increase Likely no change Unknown Probable no change (uncertain) Probable decrease (uncertain) Unknown Definite increase Probable increase (uncertain) Definite no change Unknown Unknown Body fat Probable no change (uncertain) Likely no change Stature Likely no change Unknown Unknown Potential Benefits and Risks VARIABLES EFFECTS Sports Performance Prevention of Injury Improvements in performance Diminished susceptibility in injuries Recommended for girls as part of osteoporosis prevention Rehabilitation from Injury Injury Risk (weightlifting) Accelerated rehabilitation after injury Moderate: unsupervised conditions and during competitive lifting Low: supervised and properly prescribed programmes Cardiorespiratory Illness No effect or possible improvement depending on the nature of the training programme Not likely in properly-instructed, supervised and prescribed programmes No proven detrimental effect Weightlifting Blackout Resting Blood Pressure Goals • Maintain activity • Enjoy movement • Develop lifelong activity habits Guidelines: Children and Adolescents • No formal resistance training for children less than 6 to 7 years old • At age 6 to 7, introduce the concept of exercise initially without weights using light weights • Maintain close and continuous supervision by a trained personnel or a parent who has received instructions • Focus on proper form, exercise technique, and safety: alignment, stabilization, and controlled motion Guidelines: Children and Adolescents • Perform warm-up and cool down for 5 to10 mins • Low exercise loads of at least 8 to 12 or 12-15 repetitions • Perform 1 to 2 sets of each exercise allowing rest periods of about 3 minutes between sets • Frequency limited to 2 exercise sessions per week • Initial progression through increasing repetitions, not resistance; or increasing the total number of exercise increase resistance by 5% at a time • Gradually progress activities Guidelines: Children and Adolescents • Provide a variety of activities that target larger muscle groups, multi-joint, combined exercises • Focus on active, creative, enjoyable play in very young children • Encourage children >6 yrs to accumulate a minimum of 30 minutes of at least moderateintensity activity in most, if not all, days of the week • Encourage older children to participate in 2030 minutes of higher intensity activity at least 3x a week Specific Guidelines • Encourage resistance training as only one of a variety of normal recreational and sport activities • Encourage using a variety of different training modalities (free weights, body weight, etc) • Discourage inter-individual competition, and stress the importance of personal improvement Specific Guidelines • Discourage extremely high intensity (loading) efforts • Avoid isolated eccentric training • Encourage a circuit system approach to capitalize on possible cardiorespiratory benefits Precautions: Children and Adolescents • Ensure safety as children are anatomically, physiologically, and psychologically immature – Use appropriate equipment, match activity to maturation or skill level, provide adequate skill preparation • Children are less tolerant to high heat load and increased susceptibility to hypothermia in a cold environment – Limit strenuous prolonged exercise, provide good hydration, and use appropriate clothing Documentation _____ x ______ x _____ x ______, ______ type mode or form of resistance exercise intensity # of reps # of sets frequency amount of load that will be used number number number of of times of bouts times the the ex in a day exercise will be to be performed performed in a week Documentation Example 1 Resistance exercise of the right upper extremity muscles using free weights (dumbbell) x 10 lbs x 10 repetitions x 2 sets, thrice a week Documentation Example 2 Manual resistance exercise of the left hip flexors x 8 repetitions x 2 sets, thrice a week Documentation Example 3 Multiple angle isometrics of the right knee extensors x 7 seconds hold x 5 repetitions x 1 set, daily Muscle setting exercise of both quadriceps x 10 seconds hold x 5 repetitions x 1 set, daily Documentation Example 4 Resistance exercise of both lower-extremity muscles using elastic band (may specify initial color to use) x 10 repetitions x 3 sets, three times a week Documentation Example 5 Progressive resistive exercise of both elbow flexors using De Lorme protocol x 3 sets, twice a week THANK YOU FOR LISTENING! References American College of Sports Medicine (1998). Guidelines for exercise testing and prescription (3rd ed). Baltimore: Williams and Wilkins. Blimkie, C. J. R. (1993). Resistance training during preadolescence: Issues and controversies. Sports Medicine, 15(6), 389-407. Kisner, C., Colby, L. (2007). Therapeutic exercise: Foundations and techniques (4th ed). Philadelphia: F. A. Davis Company. Matos, N. and Winsley, R. J. (2007). Trainability of young athletes and overtraining. Journal of Sports Science and Medicine 6,353-367.