EXCI252Ch6AssessingMuscularFitnessF2023.pptx

Chapter 6 Assessing Muscular Fitness EXCI 252 1 Benefits of Muscular Fitness  Minimum levels of muscular fitness are needed:  To perform activities of daily living.  To maintain functional independence with age.  To partake in active leisure-time pursuits without undue stress or fatigue....

Chapter 6 Assessing Muscular Fitness EXCI 252 1 Benefits of Muscular Fitness  Minimum levels of muscular fitness are needed:  To perform activities of daily living.  To maintain functional independence with age.  To partake in active leisure-time pursuits without undue stress or fatigue.  Adequate levels of muscular fitness lessen the chance of developing:  Low back problems.  Osteoporotic fractures.  Musculoskeletal injuries. EXCI 252 2 ACSM’s (2022) Definition of Muscular Fitness  Muscular Fitness  refers collectively to the characteristics of strength, hypertrophy, power, and local muscular endurance.  is optimized through the implementation of resistance training, which can encompass free weights, machines, body weight, bands/tubing, or any other object that requires one to exert force against a resistance. EXCI 252 3 Muscular Endurance  is also called local muscular endurance.  is the ability of a muscle group to exert a submaximal force for extended periods.  is the ability of a muscle group to exert a given force for extended periods.  is the ability of a muscle group to maintain a specific % of the maximum voluntary contraction (MVC) for a prolonged period of time.  is the ability of a muscle group to execute repeated contractions over a period of time sufficient to cause muscular fatigue.  is the ability of a muscle group to exert submaximal force repeatedly, or sustain a static contraction without fatigue. EXCI 252 4 Muscular Strength  is the maximal force generated in a single contraction at a specified velocity.  is the ability of a muscle group to develop maximal contractile force against a resistance in a single contraction.  refers to the maximal force that can be generated by a specific muscle or muscle group.  is the peak force or torque developed during a maximal voluntary contraction (MVC). EXCI 252 5 Muscular Power  is a skill-related component of physical fitness.  is the muscle’s ability to exert force per unit of time.  is the ability to exert force rapidly.  is the rate at which mechanical work is performed.  is the maximal amount of force one can exert in the least amount of time. EXCI 252 6 Types of Muscle Action Figure 6.1 EXCI 252 7 Types of Muscle Action  Isometric or Static Muscle Action  same muscle length.  no visible movement of the joint.  Dynamic Muscle Action  muscle length changes.  visible joint movement.  auxotonic, isokinetic, or variable resistance.  Isotonic Muscle Action  traditional term used to describe the muscle action when lifting free weights.  is a misnomer because the tension produced by a muscle group during free weight exercise fluctuates greatly even though the resistance is constant throughout the range of motion (ROM).  Auxotonic Muscle Action  is defined as variable muscle tensions caused by changing velocities & joint angles.  is the correct term for describing the muscle action when lifting free weights or performing resistance exercise with a constant resistance exercise machine.  can be either concentric or eccentric. EXCI 252 8 Auxotonic Muscle Action  Concentric Muscle Action  resistance < force produced by muscle group.  muscle shortens during tension development.  e.g., weight is lifted.  Eccentric Muscle Action      resistance > force produced by muscle group. muscle lengthens during tension development. resist gravity. braking force to decelerate rapidly moving body segments. greater risk of injury.  e.g., weight is lowered. EXCI 252 9 Auxotonic Muscle Action Figure 6.2. Strength of the knee flexors in relation to knee joint angle. EXCI 252 10 Auxotonic Muscle Action  Free-weights  Constant-resistance exercise machines Figure 6.3 (a). EXCI 252 11 Isokinetic Muscle Action  is a maximal contraction of a muscle group at a constant velocity throughout the entire range of joint motion.  can only be performed on an isokineticresistance exercise machine called an isokinetic dynamometer. Figure 6.3 (b). EXCI 252 12 Purposes of Strength & Muscular Endurance Assessment  Establish baseline values before training.  Monitor progress during training.  Assess the overall effectiveness of:  resistance training &  exercise rehabilitation programs. EXCI 252 13 Tests that Assess Strength & Muscular Endurance are Specific to the:  Muscle or Muscle Group Tested  Type of Muscle Action  Static or dynamic muscle action.  Velocity of Muscle Movement  Slow or fast movement.  Type of Test  Strength or endurance test.  Type of Equipment  Free weights, constant-resistance exercise machines, variable-resistance exercise machines, or isokinetic-resistance exercise machines.  Joint’s Range of Motion (ROM)  Static or dynamic muscle action. EXCI 252 14 Absolute and Relative Muscular Strength  Absolute Muscular Strength  = MVC in Newtons or kg  Relative Muscular Strength  = MVC / Body Mass EXCI 252 15 Isometric Muscle Testing  Spring-Loaded Dynamometers  Handgrip Dynamometer  Back & Leg Dynamometer  Hydraulic Dynamometers  Cable Tensiometers  Digital Handheld Dynamometer  Clinical Methods  Load Cells (Strain Gauges) EXCI 252 16 Isometric Muscular Strength  is measured as the maximum force exerted in a single contraction against an immovable resistance (i.e., maximum voluntary contraction, or MVC).  is the maximal force produced by a muscle group when the limb is not rotating (zero velocity). EXCI 252 17 Spring-Loaded Dynamometers  An external force applied to the dynamometer compresses a steel spring & moves an indicator needle or pointer.  The force required to move the pointer a given distance determines the external force applied to the dynamometer. EXCI 252 18 Spring-Loaded Handgrip Dynamometer  Measures forces from 0 to 100 kg in 1.0-kg increments. EXCI 252 19 Handgrip Strength Testing  Handgrip Strength  is a measure of isometric strength.  is a widely used indicator of total body strength.  been shown to be predictive of functional limitations and disability later in life.  was a stronger predictor of all-cause and cardiovascular mortality than systolic blood pressure in a large longitudinal population study conducted in 17 countries (Leong et al., 2015). EXCI 252 20 Handgrip Strength Testing Procedures  Protocol 1 (ASHT, 1992)  Seated or stand erect  Protocol 2 (CSEP,  Stand erect  Shoulder adducted & neutrally rotated  Elbow of test arm is flexed at 90o  Forearm in neutral position  Slight wrist extension  0 to 30o  3 trials per hand  Record the mean of 3 trials 2021)  Arm slightly abducted in a neutral position  Test arm is straight  2 trials per hand, alternating hands  Record maximum score for each hand to the nearest 1 kg  Combine the maximum scores from the left & right hands EXCI 252 21 Spring-Loaded Back & Leg Dynamometer  Measures forces from 0 to 1,134 kg in 4.5-kg increments. EXCI 252 22 Leg & Back Strength Testing Procedures   Leg Strength     Back Strength     Stand on platform Erect trunk Flexed knees (130o - 140o) Pronated grip on hand bar  Slowly exert as much force as possible while extending the knees without using the back  2 or 3 trials  1 min rest between trials  Choose MAX score & convert it to kg Stand on platform Head & trunk erect Knees fully extended Alternated grip  Rt hand = pronated  Lt hand = supinated  Pull the hand bar straight upward using the back muscles without leaning backward  2 trials  1 min rest between trials  Choose MAX score & convert it to kg EXCI 252 23 Static Strength Norms for Spring-Loaded Dynamometers EXCI 252 24 Handgrip Endurance Testing Procedures Maximal Force (MVC) Submaximal Force (% MVC) Squeeze the handle maximally for 1 minute. Record the initial & final forces. Squeeze the handle at a submaximal force for as long as possible. Relative endurance score = (Final force / Initial force) x 100 Relative endurance score = time that the %MVC is maintained. EXCI 252 25 Hydraulic Dynamometers  are an alternative to spring-loaded dynamometers that can be used to measure isometric grip strength.  have a sealed hydraulic system that measures force (lb or kg) on a gauge dial.  Example  Jamar handgrip dynamometer EXCI 252 26 Jamar Handgrip Dynamometer  is widely used & has excellent validity & reliability.  is widely regarded as the gold standard for handgrip dynamometers among clinicians.  may not be appropriate to measure isometric strength for individuals with a weak MVC because the resolution of the device is too large to detect small changes in strength.  Myogrip Dynamometer (Hogrel, 2015)  is recommended for clients with a weak MVC. EXCI 252 27 Cable Tensiometer  is an instrument that measures force in an isometric muscle action.  provides the advantage of versatility for recording force measurements at virtually all angles about a specific joint’s ROM.  can be used to assess static strength of 38 different muscle groups throughout the body.  Increasing the force on the cable depresses the riser over which the cable passes. This deflects the pointer & indicates the subject’s strength score. EXCI 252 28 Cable Tensiometer Instrumentation  Tensiometer  Wall  Steel  Straps cables  Testing table hooks  Goniometer EXCI 252 29 Cable Tensiometry Tests  can be used to 1. assess strength impairment at specific joint angles, 2. monitor progress during rehabilitation. EXCI 252 30 Digital Handheld Dynamometry  is a convenient method for measuring the isometric strength of the upper & lower body musculature.  provides a digital display of force production to assess the isometric strength of 11 muscle groups (Appendix C.1):       Elbow flexors & extensors, Shoulder extensors & abductors, Wrist extensors, Hip flexors, extensors, & abductors, Knee flexors, extensors, & Ankle dorsiflexors. EXCI 252 31 Digital Handheld Dynamometry  Measures force up to a maximum of 1334 newtons (300 lb in 0.1-lb increments). EXCI 252 32 Clinical Methods  The following clinical tests have been developed to measure the isometric endurance of core muscles used to stabilize the spine:  V-Sit Test – trunk flexors,  Sorensen Test – trunk extensors,  Side Bridge Test – lateral flexors. EXCI 252 33 Clinical Methods V-Sit Test Sorensen Test Trunk is reclined 60o Knees & hips flexed 90o Bench height = 25 cm Side Bridge Test  Novel Side-Support Test  feet are elevated on a 15-cm padded stool.  developed by Greene & colleagues to avoid the disadvantage of the side bridge test: some clients terminate the test because of upper extremity fatigue or pain. (Evans, K. et al. Journal of Science & Medicine in Sport.10: 447-455, 2007) EXCI 252 34 Assessment of Dynamic Muscular Strength & Endurance 1. Free Weights  recommended to test dynamic muscular strength & endurance. 2. Constant-Resistance Exercise Machines  recommended to test dynamic muscular strength & endurance. 3. Variable-Resistance Exercise Machines  not recommended to test dynamic muscular strength & endurance. 4. Free-Motion Exercise Machines 5. Isokinetic-Resistance Exercise Machines 6. Calisthenic-Type Exercise Tests EXCI 252 35 Free Weights & Constant-Resistance Exercise Machines  Auxotonic Dynamic Exercise  Can also be called dynamic constant external resistance (DCER) exercise.  During this type of exercise, the muscle group does not contract maximally throughout the ROM.  Major Disadvantage  They measure dynamic strength only at the weakest point in the ROM.  Explanation  The resistance cannot be varied to account for fluctuations in muscular force caused by the changing mechanical (angle of muscle pull) & physiological (muscle length) advantage of the musculoskeletal system during the movement. EXCI 252 36 Free Weights & Constant-Resistance Exercise Machines Changes in Mechanical Advantage During Elbow Flexion EXCI 252 37 Advantages & Disadvantages of Constant-Resistance Exercise Machines Compared to Free Weights  Advantages  CREMs require less neuromuscular coordination to stabilize body parts & maintain balance.  CREMs do not require spotting.  Disadvantages  CREMs limit an individual’s ROM & plane of movement.  Some CREMs have relatively large weight plate increments.  Some CREMs cannot accommodate individuals with short limbs, long limbs, a large body, & large limb circumferences. EXCI 252 38 Dynamic Muscular Strength Testing  Force Plates + Linear Transducers  Tendo Weightlifting Analyzer System  Myotest Accelerometer  1-Repetition Maximum (1-RM)  Estimation of 1-RM  Relative strength: 1-RM / Body Mass EXCI 252 39 Force Plates + Linear Transducers  used to obtain direct measures of muscular force & power.  the gold standard of measuring dynamic muscle strength & power.  are expensive due to cost of equipment.  used in a laboratory setting. EXCI 252 40 Tendo Weightlifting Analyzer System  is a linear transducer that can be attached to the end of a barbell.  is a reliable & valid device to evaluate lifting movement velocity, muscle force, & power during dynamic resistance exercise in a field setting. EXCI 252 41 Myotest Accelerometer  has the potential to measure force production in 3 different planes of movement.  has a high validity & reliability for measuring dynamic muscular strength & power during resistance exercise.  is a practical device to evaluate lifting velocity, muscle force & power in a field setting. EXCI 252 42 1-Repetition Maximum (1-RM)  more commonly used in field settings to measure dynamic muscular strength.  obtained through trial & error.  can be used to:  rate health status,  establish exercise prescription workloads, and/or  monitor a resistance training program.  is the heaviest weight that can be moved only once through the full ROM in a controlled manner with good posture.  is the maximum weight that can be lifted for one complete repetition of the movement with proper technique.  is time-consuming.  may be underestimated for clients with little or no resistance exercise experience.  is outside of the Scope of Practice of a CSEP-CPT. EXCI 252 43 Steps for 1-RM Testing  Warm-Up Sets     5-10 reps at 40%-60% of estimated 1-RM Rest 1 min 3-5 reps at 60%-80% of estimated 1-RM Rest 2 min  Attempt a 1-RM lift  Rest between 1-RM attempts = 2-4 min  If successful, increase weight conservatively  Upper body: 5%-10%  Lower body:10%-20%  Continue until client fails to complete the 1-RM lift.  Typically, the 1-RM is achieved within 3 to 5 trials (attempts). EXCI 252 44 Valid Measures of Dynamic Muscular Strength  Upper Body Strength  1-RM Bench Press (ACSM, 2022)  1-RM Military Press (ACSM, 2022)  Lower Body Strength  1-RM Leg Press (ACSM, 2022)  1-RM Back Squat (ACSM, 2022)  1-RM Leg Extension EXCI 252 45 Relative Strength: 1-RM / Body Mass  Six Test Items  Bench press, Arm curl, Latissimus pull,  Leg press, Leg extension, & Leg curl.  Express & evaluate the 1-RM as a % body mass for each exercise: [Strength (lb) / body mass (lb)].  Using Table 6.6, determine the number of points corresponding to the strength-to-body mass ratios for each exercise.  Add the total points to establish the overall strength & fitness category of your client. EXCI 252 46 Relative Strength: 1-RM / Body Mass EXCI 252 47 Estimation of 1-RM  1-RM can be estimated using:  Submaximal muscular endurance tests   YMCA Bench Press Test Muscular endurance is directly related to muscular strength.  1-RM prediction equations  Prediction tables   Perform multiple-RM tests. Table 6.13 - Average number of repetitions & %1-RM values. EXCI 252 48 Estimation of 1-RM  Brzycki (1993) 1-RM Prediction Equation for Men  1-RM = (Weight lifted in lb) / [1.0278 - (Fatigue REPs x 0.0278)]  REPs 10.  Brzycki (2000) 1-RM Prediction Equation  Based on the # of reps to fatigue obtained in 2 submaximal sets.  1-RM = [(SM1 – SM2) / (REP2 – REP1)] x [(REP1 – 1) + SM1]  REPs 10.  Kim et al. (2002) Gender-Specific 1-RM Prediction Equations  Men  1-RM (kg) = (1.55 x YMCA Test REPs) + 37.9  Women  1-RM (kg) = (0.31 x YMCA Test REPs) + 19.2 EXCI 252 49 Estimation of 1-RM  Use the average # of reps corresponding to various percentages of 1-RM in Table 6.13.  Estimate 1-RM from 2-RM to 10-RM values:  Estimated 1-RM = [Weight lifted / (%1-RM/100)]  Limitation: a marked variation exists in the # of reps that can be performed at a fixed % of a 1-RM for different muscle groups. EXCI 252 50 Estimation of 1-RM EXCI 252 51 Estimation of 1-RM  Determine the %1-RM from the number of reps completed by this client using Table 6.13 from your textbook.  Divide the weight lifted by the % 1-RM.  Bench Press: the client performed 10 repetitions of 90 lbs.  10 repetitions = 75% 1-RM.  1-RM = 90 lbs lifted/0.75.  1-RM = 120 lbs.  Leg Press: the client performed 4 repetitions of 240 lbs.  4 repetitions = 90% 1-RM.  1-RM = 240 lbs lifted/0.90.  1-RM = 267 lbs. EXCI 252 52 Variable-Resistance Exercise Machines % Maximum Force Strength Curve for Elbow Flexion  Theory The muscle contracts maximally throughout the entire ROM by varying the resistance to match the exercise strength curve.  Accommodating Resistance To develop maximal tension throughout the complete range of motion (ROM) rather than at a particular point (weakest point). Joint Angle (degrees) EXCI 252 53 Variable-Resistance Exercise Machines  Automatically change the resistive force throughout the ROM:  Provide proportionately less resistance in weaker segments of the ROM.  Provide proportionately more resistance in stronger segments of the ROM.  Overcomes the main limitation of auxotonic resistance exercise:  the sticking point.  Have a moving connection between the resistance & the point of force application:  Lever, Cam, or Pulley. EXCI 252 54 Variable-Resistance Exercise Machines  Cam  is an ellipse connected to the movement arm of the machine on which the cable or belt travels.  provides variable resistance.  changes how heavy the weight feels as the lifter moves through the complete ROM.  Each joint movement has an associated strength curve.  The strength of the agonist muscle varies at different angles of the joint. EXCI 252 55 Variable-Resistance Exercise Machines A cam with variable lever arms. Source: Zatsiorsky, V.M., and Kraemer, W.J. (2006). Science and Practice of Strength Training. 2nd ed. Champaign, IL: Human Kinetics. EXCI 252 56 Limitations of Variable-Resistance Exercise Machines  The Cams of many machines are incorrectly designed.  Many of these machines fail to match the strength curves of different muscle groups.  The resistance offered by the Cams does not match average strength curves.  Difficult to assess maximal muscle force or strength.  Limited usefulness for maximal strength testing. EXCI 252 57 Dynamic Muscular Endurance Testing  Repetitions to Failure  at a given % of Body Weight or 1-RM.  Pollock, Wilmore, & Fox (1978) recommend using a weight at 70% 1-RM for each exercise.  YMCA (Golding, 2000) Bench Press Test  uses a flat bench & barbell.  client performs as many repetitions as possible.  cadence set at 30 reps/min.  is terminated when the client cannot maintain the exercise cadence.  Loads  Male clients: 80 lb (36.4 kg) barbell.  Female clients: 35 lb (15.9 kg) barbell. EXCI 252 58 Dynamic Muscular Endurance Testing  Use a Test Battery  consists of 7 items.  Arm curl, Bench press, Lat pull-down, Triceps extension, Leg extension, Leg curl, and Bent-knee sit-up.  lift a % of client’s body mass up to a max of 15 reps.  refer to Table 6.8 for percentages for each test item. EXCI 252 59 Dynamic Muscular Endurance Testing EXCI 252 60 Dynamic Isokinetic Muscle Testing Cybex II Isokinetic Dynamometer  Involves the assessment of maximal muscle tension throughout a range of joint motion set at a constant angular velocity (degrees·sec-1).  The muscles are maximally loaded throughout the complete ROM by an isokinetic-resistance exercise machine called an isokinetic dynamometer. EXCI 252 61 Isokinetic Dynamometers  Provide an accurate & reliable assessment of strength, endurance, & power of muscle groups.  The speed of limb movement is kept at a constant preselected velocity.  The velocity can be set at a value ranging from 0 to 300 degrees·sec-1.  The machine matches the force produced by the individual’s muscles so that the preselected velocity is maintained throughout the ROM.  The resistance counteracting the individual’s force production is called accommodating resistance.  Peak torque (force), total work, & power can be evaluated from the recorded output. EXCI 252 62 Isokinetic-Resistance Exercise Test Protocols Isokinetic Tests Strength Speed Setting (degrees/sec) 30 or 60 Protocol Measure 2 submax practice trials followed by 3 max trials Peak torque (ft-lb or Nm) Endurance 120 to 180 1 max trial # reps until torque reaches 50% initial torque value Power 120 to 300 2 submax practice trials followed by 3 max trials Peak torque (ft-lb or Nm) EXCI 252 63 Limitations of Isokinetic-Resistance Exercise Machines  Expensive equipment.  Found primarily in laboratory settings or sports medicine clinics.  Only permits angular motion.  No isokinetic muscle actions occur in real-life movements.  Angular velocity is relatively low compared to athletic movements. EXCI 252 64 Muscle Imbalance  May compromise joint stability.  Increase the risk of musculoskeletal injury. EXCI 252 65 Muscle Balance Ratios  Differ among muscle groups.  Are affected by the force-velocity of muscle groups at specific joints.  The difference in strength between contralateral (right & left sides) muscle groups should not be more than 15%.  The strength-to-body-mass (BM) ratio of the upper body should be at least 40% of lower body relative strength:  = (Bench press 1-RM / BM) / ( Leg press 1-RM / BM)  Isokinetic dynamometers have been used to assess muscle imbalances of agonist and antagonist muscle groups (see the next slide).  In field settings, a crude index of muscle balance may be obtained by comparing 1-RM values of muscle groups. EXCI 252 66 Muscle Balance Ratios Recommended for Agonist & Antagonist Muscle Groups Muscle Groups Muscle Balance Ratio Hip extensors & flexors 1:1 Elbow extensors & flexors 1:1 Trunk extensors & flexors 1:1 Ankle inverters & everters 1:1 Shoulder flexors & extensors 2:3 Knee extensors & flexors 3:2 Shoulder internal & external rotators 3:2 Ankle plantar flexors & dorsiflexors 3:1 The muscle balance ratios are based on isokinetic tests of peak torque production at slow speeds (30 to 60 degrees·sec-1). EXCI 252 67 Calisthenic-Type Strength & Muscular Endurance Tests  Dynamic Muscular Strength Tests  assess dynamic muscular strength using calisthenic-type exercises.  accomplished by determining the max weight, in excess of body mass, that can be lifted for 1 rep of the movement.  for each test, attach weight plates of 2.5, 5.0, 10.0, & 25.0 lb to the individual.  Dynamic Muscular Endurance Tests  assess dynamic muscular endurance by measuring the max # of reps of a calisthenic exercise performed by an individual. EXCI 252 68 Calisthenic-Type Strength & Muscular Endurance Tests Dynamic Strength Tests      Pull-up Dip-strength Sit-up Push-up Bench squat Dynamic Endurance Tests      Pull-ups Sit-ups Trunk curls Partial curl-ups Push-ups EXCI 252 69 Calisthenic-Type Muscular Endurance Tests  Alternatives to pull-up tests when a client is unable to perform 1 pull-up:  Modified Pull-Up (Baumgartner, 1978)  Flexed-Arm Hang Test • Measures isometric endurance of the arm & shoulder girdle muscles. • Scored as the amount of time that is maintained in the flexed-arm hanging position. • Grip on the pull-up bar o Pronated grip (traditional) o Supinated grip EXCI 252 70 Modified Pull-Up (Baumgartner, 1978) (Baumgartner, T.A. Modified pull-up test. Research Quarterly, American Alliance for Health, Physical Education, and Recreation. 49(1): 80-84, 1978.) EXCI 252 71 CSEP-PATH (2021) Musculoskeletal Fitness Assessment Test Measures Measurement Sensitivity Contraindications Grip Strength (15 to 69 yr) Isometric strength (hand grip, forearms). Nearest 1.0 kg. Injury to the wrist.* 2 trials per hand Push-Ups (15 to 69 yr) Dynamic muscular endurance (chest, shoulders, & arms). Nearest 1 repetition. Lower back pain, shoulder/wrist injury, osteoporosis.* Complete as many pushups as possible with good form. Predicted 1-RM Estimates strength specific to muscle or muscle groups being tested. Depends on the type of equipment used. Injury to shoulder or knee, osteoporosis.* Predicted 1-RM should be achieved in 3 attempts. Vertical Jump (15 to 69 yr) Peak leg power Nearest 0.5 cm. Lower back pain, knee/ankle injury, osteoporosis.* 3 trials of a static squat jump (10-15 seconds rest between trials). Select the best jump of the 3 trials. Ability to contract the leg muscles with speed and force in one explosive action. Number of Trials Back Extension (15 to 69 yr) Isometric muscular endurance (trunk extensor muscles) of upper body. Nearest 0.1 second. Cannot meet the prescreen requirement or current back discomfort or pain. Hold proper position as long as possible to a maximum of 3 minutes. Forearm Plank Isometric muscular endurance of “core” abdominal muscles. Nearest 0.1 second. Lower back pain, shoulder/elbow injury, osteoporosis.* Hold proper position as long as possible. *Injury or condition that prevents the client from completing the test safely, pain-free, & with proper technique. EXCI 252 72 Dynamic Muscular Power Testing  Vertical Jump  Equipment  Colored chalk on the fingers, measuring tape,  Vertec (commercially available) device,  Switch mat or contact mat, or  Myotest accelerometer.  Variations of the Vertical Jump Test  Drop-Step Vertical Jump test  Static Vertical Jump test  Countermovement Vertical Jump test  Most commonly used jump test version for assessing muscular power.  Standing Long Jump EXCI 252 73 Sources of Measurement Error in Muscular Fitness Testing  Client Factors  Equipment  Technician Skill  Environmental Factors EXCI 252 74 Client Factors  Familiarization with equipment & testing procedures  Weightlifting experience  Lifting technique  Give a maximal effort  Adequate rest between trials  Restrict drugs & medications  Motivate during testing EXCI 252 75 Equipment  Design of the testing equipment:  Most of the dynamic strength & muscular endurance protocols & norms presented in this chapter were developed using constant-resistance exercise machines.  Calibration of equipment.  Inspection & maintenance of equipment.  Selection of exercise machines that can accommodate various body dimensions:  limb lengths & body sizes. EXCI 252 76 Technician Skill    Qualified Trained Knowledgeable:  Proper lifting technique  Spotting technique  Standardized testing procedures  Explanation & Demonstration:  Proper lifting technique.  Observation & Correction of Performance Errors:  Prevent cheating  Starting position (Bench press, Push-ups)  Grip width (narrow vs. wide)  Grip type (pronated vs. supinated) EXCI 252 77 Environmental Factors  Room Temperature  Humidity  Clean  Quiet EXCI 252 78