Muscular Strength & Endurance

Muscular Strength & Muscular Strength & EnduranceEndurance

Fitness ConceptsFitness Concepts

PEAC 1621PEAC 1621

Kirk EvansonKirk Evanson

Muscle PhysiologyMuscle Physiology

MuscleMuscle Composition and OrganizationComposition and Organization

Muscle fiber (muscle cell)- composed of myofibrilsMuscle fiber (muscle cell)- composed of myofibrils Myofibrils → muscle fibers → fascicles → musclesMyofibrils → muscle fibers → fascicles → muscles

Muscle fiber typesMuscle fiber types Slow-twitch (aerobic)- relatively fatigue resistant, but Slow-twitch (aerobic)- relatively fatigue resistant, but

they don’t contract as rapidly or strongly as fast-twitch they don’t contract as rapidly or strongly as fast-twitch fibers.fibers.

Fast-twitch (aerobic or anaerobic)- contracts more Fast-twitch (aerobic or anaerobic)- contracts more rapidly and forcefully than slow-twitch fibers but rapidly and forcefully than slow-twitch fibers but fatigue more quickly.fatigue more quickly.

Muscle PhysiologyMuscle Physiology

MuscleMuscle Most muscles contain a mixture of slow-twitch and Most muscles contain a mixture of slow-twitch and

fast-twitch fibersfast-twitch fibers Endurance activities (e.g. jogging, swimming) Endurance activities (e.g. jogging, swimming)

primarily utilize slow-twitch while power activities primarily utilize slow-twitch while power activities (e.g. weight lifting) utilize fast-twitch(e.g. weight lifting) utilize fast-twitch

Motor unit- the motor nerve and the muscle fibers Motor unit- the motor nerve and the muscle fibers that are innervated by that nervethat are innervated by that nerve

Benefits of Muscular Strength and EnduranceBenefits of Muscular Strength and Endurance

Injury PreventionInjury Prevention Good muscle strength in areas such as the Good muscle strength in areas such as the

abdomen, hips, lower back, and legs can support abdomen, hips, lower back, and legs can support the back in proper alignment and help prevent low-the back in proper alignment and help prevent low-back painback pain

Training also improves the strength of tendons, Training also improves the strength of tendons, ligament, and cartilage cells, which decreases the ligament, and cartilage cells, which decreases the risk for injuryrisk for injury


Improved Body CompositionImproved Body Composition Strength training improves body composition by Strength training improves body composition by

increasing muscle massincreasing muscle mass Increases in muscle mass increase basal metabolic Increases in muscle mass increase basal metabolic

rate.rate. BMR can increase up to 15%BMR can increase up to 15% The body requires more calories, therefore there is less The body requires more calories, therefore there is less

fat depositionfat deposition


Improved Muscle and Bone Health with AgingImproved Muscle and Bone Health with Aging Strength training prevents muscle and nerve Strength training prevents muscle and nerve

degeneration commonly associated with agingdegeneration commonly associated with aging Also decreases the risk of hip fracture and other life-Also decreases the risk of hip fracture and other life-

threatening injuriesthreatening injuries Decreases the progressive loss of muscle tone with Decreases the progressive loss of muscle tone with

age (sarcopenia)age (sarcopenia) By age 75, 25% of men and 75% of women will be By age 75, 25% of men and 75% of women will be

unable to lift 10 lbs.unable to lift 10 lbs. Weight training can mitigate these changesWeight training can mitigate these changes


Prevention and Management of Chronic DiseasePrevention and Management of Chronic Disease Strength training improves glucose metabolismStrength training improves glucose metabolism Modifies the risk factors for cardiovascular diseaseModifies the risk factors for cardiovascular disease

Decreases diastolic blood pressureDecreases diastolic blood pressure Positive alterations in cholesterolPositive alterations in cholesterol

Increases in HDL, decreases in LDLIncreases in HDL, decreases in LDL

Strength training improves bone mineral densityStrength training improves bone mineral density Beneficial in the prevention of osteoporosis and associated bone Beneficial in the prevention of osteoporosis and associated bone

fracturesfractures

Types of ExerciseTypes of Exercise

Static (isometric) ExerciseStatic (isometric) Exercise Involves a muscle contraction without a change in Involves a muscle contraction without a change in

the length of the muscle or the angle in the joit on the length of the muscle or the angle in the joit on which the muscle acts.which the muscle acts.

Common for early physical therapyCommon for early physical therapy Do not build muscle throughout the range of motionDo not build muscle throughout the range of motion

Dynamic (isotonic) ExerciseDynamic (isotonic) Exercise Involves a muscle contraction with a change in the Involves a muscle contraction with a change in the

length of the musclelength of the muscle


Dynamic Exercise (cont.)Dynamic Exercise (cont.) Constant resistance exerciseConstant resistance exercise

Fixed weight- easier at certain joint angles due to Fixed weight- easier at certain joint angles due to mechanical advantages based on muscle insertion points mechanical advantages based on muscle insertion points and lengthand length

Variable resistance- resistance is varied throughout the Variable resistance- resistance is varied throughout the movement to maintain intensity throughout all joint movement to maintain intensity throughout all joint anglesangles


Dynamic Exercise (cont.)Dynamic Exercise (cont.) Eccentric- involves placing a load on a muscle as it Eccentric- involves placing a load on a muscle as it

lengthenslengthens Plyometrics- the sudden eccentric loading and Plyometrics- the sudden eccentric loading and

stretching of muscles followed by a forceful stretching of muscles followed by a forceful concentric contractionconcentric contraction

http://www.atitudejiujitsu.com.br/images/ply.jpg


Dynamic Exercise (cont.)Dynamic Exercise (cont.) Isokinetic- the resistance can be moved at a fixed Isokinetic- the resistance can be moved at a fixed

speed. Measurements can be made for multiple speed. Measurements can be made for multiple muscle groups in addition to group comparisons muscle groups in addition to group comparisons (quadriceps/hamstring ratio)(quadriceps/hamstring ratio)

http://2.bp.blogspot.com/_K6GPv8xcGQE/Rcp66D8BFQI/AAAAAAAAAGQ/uuFjyHFfgLg/s320/JustinIsokineticMach1.JPG

Exercise EquipmentExercise Equipment

Free vs. Machine weightsFree vs. Machine weights Free weightsFree weights

ProsPros More muscles needed for the movementMore muscles needed for the movement Improvements made in multiple areasImprovements made in multiple areas Requires more calories than machine weightsRequires more calories than machine weights

ConsCons Movements are more complex and require more strength- the Movements are more complex and require more strength- the

risk of injury increasesrisk of injury increases Spotters may be neededSpotters may be needed

Exercise EquipmentExercise Equipment

Free vs. Machine weightsFree vs. Machine weights Machine weightsMachine weights

ProsPros Reasonably easy to performReasonably easy to perform Many safety mechanisms in place to decrease (but not Many safety mechanisms in place to decrease (but not

eliminate) the risk of injuryeliminate) the risk of injury

ConsCons The intensity of the movement has a limit- can only recruit so The intensity of the movement has a limit- can only recruit so

many muscles to do a controlled movementmany muscles to do a controlled movement It can be difficult to find the ‘perfect’ machine to work the It can be difficult to find the ‘perfect’ machine to work the

desired target areadesired target area

FITT PrincipleFITT Principle

Exercise frequencyExercise frequency 2-3 days/week2-3 days/week 48 hours of rest needed to allow for adequate 48 hours of rest needed to allow for adequate

recoveryrecovery Exercise intensity and volumeExercise intensity and volume

Repetitions and SetsRepetitions and Sets Low repetitions- maximal effort- increase in strengthLow repetitions- maximal effort- increase in strength High repetitions- medium effort- increase in muscular High repetitions- medium effort- increase in muscular

enduranceendurance

FITT PrincipleFITT Principle

Exercise intensity and volume (cont.)Exercise intensity and volume (cont.) Repetitions and SetsRepetitions and Sets

3-5 sets3-5 sets Sets can be determined based off of the intensity of the setSets can be determined based off of the intensity of the set

Type or mode of exerciseType or mode of exercise Variety is the spice of life- work multiple muscle Variety is the spice of life- work multiple muscle

groupsgroups

Exercise TrainingExercise Training

SpecificitySpecificity The body will adapt to stressThe body will adapt to stress

A leg press will not appreciably improve lower body A leg press will not appreciably improve lower body muscle endurance, however jogging willmuscle endurance, however jogging will

Exercises should be selected based off of individual Exercises should be selected based off of individual exercise goalsexercise goals

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Muscular Strength & Endurance