Scientific Basis for Improving Muscular Strength and Endurance

Question 1

Introduction to Resistance Training

Answer 1

• PTs address issues of muscular performance: strength, endurance, power, resistance exercise
• strong theoretical background allows common language, practical application of muscle training

Question 2

Strength

Answer 2

• defined as max voluntar force produced by NM system: 1 RM
• increased strength occurs secondary to lifting heavy loads, for relatively low repetitions, involves complex set of interactions (neurological, muscular, biomechanical)
• numerous benefits associated with PRE

Question 3

Benefits of Resistance Training

Answer 3

• only PRE maintains muscle mass through adulthood
• untrained lose 5-7 lb of muscle every decade
• only PRE slows muscle loss associated with decreased RMR
• untrained show 2 to 5% decrease every decade
• increase 3 lb muscle mass which increases RMR by 7% and daily caloric requirements by 15%
• adults who strength train burn more calories all day long
• most adults do not use PRE yet can replace muscle mass lost through inactivity
• PRE found to increase total muscle area by 11.4% in previously untrained
• improves body composition by increasing fat-free weight
• appropriate use shown to increase bone mineral density and CT strength
• increases glucose uptake
• alters and enhances skeletal muscle carbohydrate metabolism, insulin action
• increases GI transit time 56% in 3 months, delayed GI transit time is linked to increased risk of colon cancer
• shown to decrease RBP
• improvements in blood lipid profiles similar to aerobic exercise

Question 4

Muscular Adaptation to PRE

Answer 4

-increased ability to generate force after RPE due to hypertrophy of muscle: increased cross-sectional area, increased synthesis of actin and myosin

Question 5

Isometric Resistance Exercise

Answer 5

• static muscle action: no change in joint angle
• studies typically show static strength gains…
• muscle at optimal length
• holding for 5-6 seconds
• 60-100% MVC (maximum voluntary contraction) show fastest gains
• 35-60% of MVC show slow increase
• 20-35% of MVC maintain strength
• less than 20% lose strength
• men increase 6%/week and women 4%/week

Question 6

Isometric Resistance Programs: Advantages

Answer 6

• requires little time
• no expensive equipment needed
• can be performed anywhere
• usually causes little soreness
• easy to maintain

Question 7

Isometric Resistance Programs: Disadvantages

Answer 7

• poor strength development through ROM
• no training of nervous system in a movement
• progress is difficult to assess without cable tensiometer (i.e. training is boring)
• can produce high SBP and DBP
• isotonic and isometric produce greater, more functional strength gains

Question 8

Isotonic Exercise Programs

Answer 8

• train muscles through available joint ROM

- external load remains constant

Question 9

Advantages of Isotonic Programs

Answer 9

• most common form of resistance training used by healthcare and exercise professionals
• builds strength throughout a ROM
• provides some training of nervous system
• progress is easy to follow as weight is added
• can be adapted to mimic functional motions

Question 10

Disadvantages of Isotonic Programs

Answer 10

• moderately expensive
• often results in soreness
• may expose novices to injury
• longer training sessions
• entire ROM not maximally trained secondary to sticking points (part where motion is most difficult)

Question 11

Isokinetic Exercise Programs

Answer 11

• train muscles through available joint ROM
• limb velocity remains constant
• velocity controlled by dynamometer
• limb velocity and force values recorded by microcomputer

Question 12

Advantages of Isokinetic Programs

Answer 12

• max resistance at all points in ROM
• can be performed at different speeds
• same device can test full spectrum of muscles
• provide a force readout for analysis

Question 13

Disadvantages of Isokinetic Programs

Answer 13

• very expensive
• can test only onemuscle
• often limited to open-kinetic chain motion
• affords little re-training of movement dysfunction
• non functional strength?

Question 14

Exercise Training Principles

Answer 14

• overload
• intensity and volume
• specificity
• cross training
• overtraining
• precautions

Question 15

Overload

Answer 15

• cells possess capacity to adapt to external stimula
• increased training load challenges an individuals current level of fitness
• initial response is fatigue and adaptation to training load
• overload causes fatigue, recovery, and adaptation
• overload is increase in training load leading to adaptation in muscle, etc
• its called PRE

Question 16

Overload for Increasing Muscular Strength

Answer 16

• tension is the stimulus
• inactivity –> lose 2-3% of strength/day
• recommended loads: 60-85% of 1RM
• attempt to increase loads or reps in every session
• best results occur with 8-12 reps
• if less than 12 increase weight
• low reps with high load

Question 17

Overload for Increasing Muscular Endurance

Answer 17

• high reps with low load
• recommended load: 15-40% of max
• work to fatigue
• tends to be boring
• need to watch for overexertion and substitution

Question 18

Intensity

Answer 18

• strength of stimulus, quality of effort, concentration of work per unit time
• ex of quantification of intensity…
• endurance or speed expressed as % VO2max
• maximum HR
• speed in m/s
• strength
• vertical jump

Question 19

Volume

Answer 19

• amount of training performed, sum of all repetitions or their duration
• ex of quantification of volume…
• kg lifted
• meters run
• number of throws or jumps taken
• number of sets and reps performed
• minutes or hours of training time

Question 20

Intensity and Volume

Answer 20

• use small loads (low intensity) with beginners or deconditioned, avoid too much overload, avoid possible injury
• take care in recommending too great an increase in either intensity or volume

Question 21

Specificity

Answer 21

• aka as specific adaptation to imposed demands (SAID) principle
• nature of training load determines training effect
• each type of training has its own specific training effect
• load must be specific to individual and activity for which they are training
• design program to meet demands or expectations
• consider energy demands, biomechanics of equipment, and functional carryover

Question 22

Overtraining

Answer 22

• progressive increase in training stimulus necessary to increase functional level
• yet individual may not take sufficient time to fully recuperate after chronic bouts of training
• occurs when body’s adaptive mechanisms repetitively fail to cope with chronic training stress
• may result in decreased performance, undue fatigue, possible substitution patterns, or injury

Question 23

Additional Principles of Training

Answer 23

• perform each rep thru full ROM
• speed of execution–>type of strength gain
• include eccentric contractions
• avoid jerky movements
• design workouts from larges to smallest

Question 24

Precautions

Answer 24

• client should not hold breath during exertion
• exhale during lift, inhale during recovery, breathe during exercise
• muscle soreness may develop secondary to exercise
• delayed onset muscle soreness develops 24-48 h after exercise, resolves within a week, linked to eccentric exercise

Question 25

Periodization

Answer 25

• gradual cycling or phasing of specificity, intensity, and volume of training
• based on Seyle’s GAS
• goal is optimal development of performance capacities
• helps prevent plateau in performance, overtraining, or injury
• consists of periodic changes of objectives, tasks, and content of training
• division of training year to meet specific objectives
• plan that changes workout sessions at regular time intervals
• training year typically comes to a definitive climax to a competitive season
• principles not limited to PRE

Question 26

Periodization: Preparation Phase

Answer 26

• goal is major gain in strength to provide foundation for obtaining: power, muscular endurance, speed, and skill
• facilitates NM adaptation through high volume of activity
• training done ~3 times per week
• employs gradual shift in emphasis from volume to intensity and skill

Question 27

Periodization: Competition Phase

Answer 27

• goal is to avoid de-training effects during competitive season
• PRE progresses to minimum maintenance phase while sport-specific skill training takes priorit
• PRE sessions decrease to 2 times per week, usually less than 20-30 minute
• total number of sets kept low: depends on goal of strength/power vs endurance; 1-4 sets; reps vary low to high-5-8 for strength/power, 10-25 for endurance
• longer rest periods between sets

Question 28

Periodization: Active Rest

Answer 28

• individuals are psychologically and physiologically fatigued after long season
• engage in active rest for at least 4 weeks
• train so as to not lose overall fitness but volume and intensity are low

Question 29

Periodization and Exercise Professionals

Answer 29

• application not limited to high level athletes
• understanding principles can help prevent injuries
• understanding can also help shape rehab programs

Question 30

Sample PRE Programs

Answer 30

• many approaches to PRE
• structure of program depends upon ultimate goal
• professionals are limited only by understanding of underlying basic sciences and creativity

Question 31

DeLorme and Watkins

Answer 31

• fathers of PRE
• same number of reps but increase % of RM from 50 to 75 to 100 over three sets
• training frequency 3d/wk
• rest period between sets 1-2 minutes
• rest between workouts 48 hrs
• resistance exercises may remain constant or be mixed

Question 32

Oxford and Zinovieff

Answer 32

• regressive resistance exercise

- start at 1 RM then decrease % of RM from 100 to 75 to 50 for 3 sets with the same amount of reps

Question 33

Aggressive Resistance Training Programs

Answer 33

• used when maximal strength or muscular hypertrophy is desired
• lesser emphasis on muscular endurance
• common in competitive weightlifting, football, track and field, and bodybuilding

Question 34

Sample Maximal Strength Program

Answer 34

• 4d/wk
• rest 3-5 min between sets
• rest 72 hours between body parts (legs: M and R, chest T and F)
• lower reps because of heavier weight trying to build bigger muscle

Question 35

Sample of Bodybuilding Program

Answer 35

• 4d/wk
• rest 1 min between sets
• rest 72 hours between body parts

Question 36

Daily Adjusted Progressive Resistance Exercise (DAPRE)

Answer 36

• form of periodization used particularly in rehab applications
• 4 sets per exercise
• set 1: 1/2 working weight: 10 reps
• set 2: 3/4 working weight: 6 reps
• set 3: full working weight: max
• set 4: adjusted working weight: max
• look at chart for guidelines on page 15

Question 37

Circuit Training

Answer 37

• employs PRE: may also include calisthenic exercises
• valued for capacity to improve muscular strength and endurance for large groups
• system produces positive changes in general fitness, muscular strength and endurance, motor performance

Question 38

Characteristics of Circuit Training

Answer 38

-based on premise that individual must do same amount of work in shorter time period
-variations exist but all have common factors…
-use of PRE
-use of physical conditioning and/or apparatus exercises
-time factor in which circuit must be completed
(common in cardiac rehab)

Question 39

Setting Up a Circuit Training Program

Answer 39

• select number and type of activities for their functional carryover
• consider worth of each for promoting balanced musculoskeletal fitness
• set up 6-12 stations, each with a specific exercise
• plan circuit so trainee can complete circuit without undue fatigue
• system easily lends itself to handling large groups efficiently
• entails some preliminary planning but requires little ongoing coordination
• clients often find it motivating-can compete against time, self or teammate
• particularly useful method for weight machines

Question 40

Implementing a Circuit Training Progarm

Answer 40

• thoroughly familiarize each client with motion to be done at each station
• perform a time trial to ascertain time needed to complete 1 to 3 laps of a circuit
• clients progress immediately from one station to the next: target time may be assigned, usually 1/3 lower than initial time trial
• weight exercises usually performed 50 to 70% of RM
• resistance usually estimated for initial trial
• may be easily changed for emphasis or client fun
• want muscular strength but really emphasize muscular endurance

Question 41

Sample Circuit Training Program

Answer 41

• to be performed continuously from exercise to exercise without rest
• 2-3 d/wk
• number of circuits 2-3
• rest between sets .5-2 min
• rest period between workouts 48 h

Question 42

Clinical Guidelines for General REsistance Exercise

Answer 42

• PRE programs address all types of muscular actions: isometric, isotonic, isokinetic
• perform systems review before starting
• prescribe at level appropriate for client
• integrate appropriate warm up and cool down
• program must have some motivational appeal

Question 43

ACSM Recommendations for PRE

Answer 43

• perform minimum of 8-10 exercises that train the major muscle groups
• workouts should not be too long
• perform one set of 8-12 reps to point of volitional fatigue
• more sets may elicit greater strength gains but additional improvement is relatively small
• perform at least 2 days a week
• adhere closely to specific exercise techniques
• elderly clients should perform the exercises in maximum ROM that does not elicit pain or discomfort
• perform exercises in a controlled manner
• maintain a normal breathing pattern
• exercise with a training partner when possible

Question 44

ACSM Recommendations for Warm-Up Exercises

Answer 44

• perform 12-15 reps with no weight before workout set with 30s to 4 m of rest before workout set
• specific warm-up is more effective for weight training than general warm-up
• no warm up set is required for high rep exercises: not as intense, serve as warm up themselves
• perform a 2nd warm up if joints and muscles involved may be more susceptible to injury