1、Muscular Strength,Maximal amount of force that can be generated by a specific muscle or muscle group in a single contraction (1RM) Important component of fitness,Reasons to Test Strength,1. Predict Performance can predict what sport you are most suited for (ie., Thorstenssen Test) 2. Implement a tra
2、ining program pre-training values training re-evaluate training etc.,Muscular Strength,3. Measure of rehabilitation measure strength pre-season injury during season use pre-season value as a guideline for rehab (“back to 100% of pre-season value”) 4. Identify Muscle Imbalance muscle imbalance may le
3、ad to injury hamstring to quadricep ratio .65-.75,Ways to Measure Strength,1. Isometric - muscle action when tension is produced but there is no change in the length of the muscle ie., hand grip dynamometer Is work being done? (FxD) no distance but physiological work is being done since we are using
4、 ATP,Isometric Testing,Advantages simple cheap saves time,Isometric Testing,Disadvantages specific to the joint angle (doesnt reflect the full ROM) doesnt correlate with sports performance more likely to perform the Valsalva Maneuver,Ways to Measure Strength,2. Isotonic muscle action in which a musc
5、le shortens or lengthens with varying tension and velocity while overcoming a constant resistance throughout a ROM ie., bench press,Isotonic,Advantages correlates better with sports performance relatively inexpensive accessible psychologically seeing work done,Isotonic,Disadvantage measuring the wea
6、kest point in the ROM doesnt measure strength at different speeds,Ways to Measure Strength,3. Isokinetically maximal tension is developed at all joint angles throughout the ROM with speed being constant (have accommodating resistance at a controlled speed of movement,Isokinetic,Advantages measure st
7、rongest point in ROM measure strength at different speeds,Isokinetic,Disadvantages expensive (40-80K) not readily accessible need someone knowledgeable to run the equipment,What Affects Strength?,1. Training Status/size of muscle fibers 2. Type of muscle action 3. Velocity 4. Joint Angle (muscle len
8、gth) 5. Fiber type 6. #Activated Motor Unit,What Affects Strength?,7. #Fibers within an activated motor unit 8. Frequency of Impulses 9. Fatigue,Training Status,Types of Muscle Actions,Static - no change in length Concentric - muscle shortening Eccentric - muscle lengthening,TYPES OF MUSCLE ACTION,M
9、uscle Action vs. Velocity,MUSCLE LENGTH vs FORCE PRODUCTION,w High aerobic (oxidative) capacity and fatigue resistance,w Low anaerobic (glycolytic) capacity and motor unit strength,w Slow contractile speed (110 ms) and myosin ATPase,Slow-Twitch (ST) Muscle Fibers,w 10180 fibers per motor neuron,w Lo
10、w sarcoplasmic reticulum development,w Moderate aerobic (oxidative) capacity and fatigue resistance,w High anaerobic (glycolytic) capacity and motor unit strength,w Fast contractile speed (50 ms) and myosin ATPase,Fast-Twitch (FTa) Muscle Fibers,w 300800 fibers per motor neuron,w High sarcoplasmic r
11、eticulum development,The difference in force development between FT and ST motor units is due to the number of muscle fibers per motor unit, not the force generated by each fiber.,Did You Know?,w Genetics determine which motor neurons innervate our individual muscle fibers.,w Muscle fibers become sp
12、ecialized according to the type of neuron that stimulates them.,w Endurance training and muscular inactivity may result in small changes in the percentage of FT and ST fibers.,What Determines Fiber Type?,w Aging may result in changes in the percentage of FT to ST fibers.,w,Frequency of Impulses,The
13、more fatigue the less strength. Is fatigue peripheral or central?,Fatigue,Muscular Strength Tests,1. Handgrip Dynamometer static,Muscular Strength Tests,2. 1RM Protocol 1. Have subject complete 5-10 reps at 40-60% of perceived 1RM 2. 1 minute of stretching 3. 3-5 reps at 60-80% of perceived 1RM 4. A
14、dd small amount of weight - attempt 5. If successful, rest 3-5 minutes and add more weight - attempt,1RM,Protocol 6. Continue “titrating” until subject is unsuccessful 7. 1RM should be determined within 3-5 maximal efforts 8. 1RM = the weight of the last successfully completed lift,Estimation of 1RM
15、 (submaximal),Submaximally estimate 1RM Advantage dont have to do max testing and not as likely to injure your athletes. Epley Equation 1RM = (0.033*Reps) Rep Wt.) + Rep Wt.),Muscular Strength Tests,3. Isokinetic Dynamometers leg extension strength at various velocities (velocity spectrum testing) 3
16、 maximal muscle actions at each velocity record the highest value of the three,Ways to Express Results,1. Absolute 2. Relative to BW 3. Relative to FFW,Muscular Endurance,Ability of a muscle group to execute repeated contractions over a period of time sufficient to cause muscular fatigue, or to main
17、tain a specific percentage of MVC for a prolonged period of time,Muscular Endurance,1. Grip Endurance 2. Sit-ups 3. Push-ups 4. Thorstensson,Grip Endurance,1. Squeeze dynamometer for 1 minute maximally - record initial strength and final strength 2. Squeeze dynamometer at a submaximal percent of MVC
18、 (ie., 60%) to fatigue,Sit-ups,Supine Knees at 90 Arms at side Fingers reaching for masking tape 8-12 cm from resting Metronome - 40 beats/min,Push-ups,Males in “up” position Females in “knee” position Hands shoulder width apart Chin touches mat As many as possible consecutively and without rest,Thorstensson,Endurance test that allows for the calculation of %FT 50 Reps 180 /sec,Thorstensson,%Decline = (Initial PT - Final PT) Initial PT ) x 100 %FT = (% Decline - 5.2) 0.9,Muscular Endurance,
