Chapter 9: Muscular Strength, Endurance, And Power Flashcards
Define muscular strength:
Ability of a muscle to generate force against some resistance
Muscle weakness or imbalance can result in…
- abnormal movement or gait
- impaired normal functional movements
Define muscular endurance:
Ability to perform repetitive muscular contractions against some resistance for an extended period.
As muscular strength increases, there tends to be a corresponding increase in _____.
Endurance
For the average person in the population, muscular _______ is likely more important because …
- endurance
- endurance is more critical in carrying out ADLs
3 types of contraction:
- isometric
- concentric
- eccentric
Describe muscle length with isometric contractions.
Muscle contracts to produce tension, but there is no change in muscle length.
Describe muscle length with concentric contractions.
Muscle shortens in length while tension increases to overcome or move some resistance.
Describe muscle length during eccentric contractions.
Resistance is greater than the muscular force being produced, and the muscle lengthens while producing tension.
Define econcentric contractions.
- Combines both controlled concentric and a concurrent eccentric contraction of the same muscle over 2 separate joints.
- only possible in 2 joint muscles
Example of a econcentric contraction:
Prone OKC hamstring curl: hamstrings cause knee flex while hip flex eccentrically to lengthen the hamstring.
Name 7 factors that determine levels of muscle strength, endurance, and power.
- size of the muscle
- # of muscle fibres
- neuromuscular efficiency
- biomechanical considerations
- age
- overtraining
- fast-twitch vs slow-twitch fibres
Describe how the size of the muscle can influence levels of muscular strength, endurance, and power.
- Muscular strength is proportional to the cross-sectional diameter of the muscle fibres.
- The size of a muscle tends to increase in cross-sectional diameter with resistance training.
Strength is a function of the ______ and ______ of muscle fibres composing a given muscle.
- #
- diameter
The number of muscle fibres in a person is a ______ characteristic; thus, a person with a larger number of muscle fibres has….
- inherited
- greater potential for hypertrophy
Initial increases in strength during the first 8-10 weeks of resistance training can be attributed primarily to:
Increased neuromuscular efficiency
What are the 3 ways that resistance training will increase neuromuscular efficiency?
- increase in # of motor units being recruited
- firing rate of each motor unit
- synchronization of motor unit firing
What are the 2 biomechanical factors that can determine amount of strength?
- position of tendon attachment
- length-tension relationship
Describe how the position of tendon attachment can affect strength.
If the tendon is attached closer o the fulcrum (joint), then it must produce a greater effort to hold weight because the length of the effort arm will be greater.
The _____ of a muscle determines the tension that can be generated.
Length
Describe how the length-tension relationship can affect strength.
If a muscle is shortened or lengthened (not at optimal length), the interaction between actin and myosin through the cross-bridges is greatly reduced, thus the muscle is not capable of generating significant tension.
At what age does muscle strength peak?
20-25 years old
After about ___ years, a person generally loses an average of ____% of his or her maximal remaining strength each year.
- 25
- 1
The loss in muscle strength related to age is related to individual levels of _____ _____.
Physical activity
How do the affects of aging change when people are physically active?
- slowed decrease in strength, cardiorespiratory endurance, and flexibility
- slowed increase in body fat
Define overtraining.
Imbalance between exercise and recovery, in which the training program exceeds the body’s physiologic and psychological limits.
How can you minimize the potential negative effects of overtraining?
- engaging in proper and efficient resistance training
- eating a proper diet
- getting appropriate rest
Slow twitch fibres AKA
- Type I
- slow-oxidative fibres
Describe slow-twitch fibres:
- resistant to fatigue
- time required to generate force is greater
- associated with long duration, aerobic type activities
Give a general description of fast twitch fibres.
- quick, powerful contractions
- fatigue rapidly
- useful in short term, high intensity activities
- anaerobic
What are the 2 types of fast-twitch fibres?
- type IIa
- type IIb
Describe type IIa fibres.
- AKA fast-oxidative-glycolytic fibres
- moderately resistant to fatigue
Describe type IIb fibres.
- AKA fast-glycolytic fibres
- fatigue rapidly
- “true” fast twitch fibres
What is the recently discovered 3rd group of fast-twitch fibres? Describe them
- type IIx
- fatigue resistant
- max power capacity less than type IIb but greater than type IIa
Muscles whose primary function is to maintain posture against gravity require more _____ and have a higher percentage of ______ ______ fibres.
- endurance
- slow twitch
Muscles that produce powerful, rapid, explosive strength movements tend to have a much higher percentage of ____ ____ fibres.
Fast twitch
How is the ratio of muscle fibre types in an individual determined?
Genetics
It is unknown whether fibre types can change, but both types of fibres can improve their _______ ______ through what types of exercises?
- metabolic capabilities
- specific strength and endurance training
Summarize the 3 theories for muscle hypertrophy.
- hyperplasia from fibres splitting in response to training (only in animals)
- increase in # of capillaries (no new capillaries formed but dormant capillaries might be filled with blood to meet increased demand for oxygen/blood)
- myofilaments theory
Define myofilaments. What are the 2 types?
- Small contractile elements of protein within the sacromere.
- thin actin and thicker myosin
Describe the myofilaments theory of hypertrophy.
- cross bridges connect actin and myosin.
- when a muscle is stimulated to contract, the cross bridges pull the myofilaments closer together = muscle shortens = movement produced
How do satellite cells play a role in hypertrophy?
- self-renewing cells
- generate population of myoblasts that are able to fuse with existing myofibres to help in facilitating growth.
Myofilaments increase in _____ and _____ as a result of resistance training, causing the individual muscle fibres to increase in _____ ______ _____.
- size
- number
- cross-sectional diameter
If resistance training is discontinued or interrupted, the muscle will ______, decreasing in both _____ and _____.
- atrophy
- strength
- mass
Adaptations in skeletal muscle that occur in response to resistance training can begin to reverse in as little as _________.
48 hours
Name 4 indirect physiologic adaptations to resistance training.
- increased strength of non-contractile structures
- increased mineral content of bone
- improved max oxygen uptake when training at sufficient intensity to elicit HR at or above training levels (minimal)
- increase in several enzymes important in aerobic and anaerobic metabolism.
Name 7 different techniques of resistance training.
- functional strength training
- isometric exercise
- progressive resistance exercise
- isokinetic training
- circuit training
- plyometric exercise
- body weight exercise
Regardless of the resistance training technique used, the AT should integrate _______ strengthening activities that involve ______, ______, _____, and _____ contractions.
- functional
- multiplanar
- eccentric
- concentric
- isometric
Describe the overload principle:
For a muscle to improve in strength, it must be forced to work at a higher level than it is accustomed to.
Without overload, the muscle will be able to ______ strength as long as training is continued, but no additional _______ ______ will be realized.
- maintain
- strength gains
The maintenance of existing levels of muscular strength may be more important in resistant programs that emphasize muscular _______ rather than ______ _____.
- endurance
- strength gains
In a rehab setting, progressive overload is limited to some degree by the ____ _____. The rate of progression is perhaps best determined by …
- Healing process
- the injured patient’s response to a specific exercise (pain, swelling = too aggressive).
The CNS controls the ability to integrate the ______ function of a number of individual muscles that must act collectively to produce a specific _____ _____ that occurs in ___ planes of motion.
- proprioceptive
- movement pattern
- 3
To understand the approach to functional strength training, the AT must understand the concept of _____ _____.
Kinetic chain
The entire kinetic chain is an _______ _______ unit, and is composed of not only muscle, tendons, ______ and ______, but also the ______ and _______ systems.
- integrated functional
- fasciae
- ligaments
- articulate
- neural
If any system within the kinetic chain is not working efficiently, the other systems are forced to _____ and ______. This can lead to tissue ______, decreased _______, and predictable patterns of ______.
- adapt
- compensate
- overload
- performance
- injury
The functional integration of the systems allow for optimal ________ efficiency during functional activities.
Neuromuscular
Functional strength training is designed to improve:
- strength
- neuromuscular control
- stabilization strength
- dynamic flexibility
A primary principle of functional strength training is to make use of training ______ to force constant _____ _______ instead of concentrating solely on morphological changes.
- variations
- neural adaptations
Exercise variables that can be changed include:
- plane of motion
- body position
- base of support
- UE or LE symmetry
- type of balance modality
- type of external resistance
An isometric contraction provides _______ strength that helps maintain normal ____ -______ and _____-______ relationships that are critical for normal joint arthrokinematics.
- stabilization
- length-tension
- force-couple
Isometric strength gains are relatively specific to …
The joint angle at which the training is performed.
It is more desirable to make use of ______ or _______ isometric exercises that involve the application of isometric force at _______ ______.
- positional
- functional
- multiple angles
Functional isometrics should be used until the healing process has progressed to the point that ____ _____ activities can be performed.
Full ROM
Isometrics parameters:
- 10s at a time
- frequency: 10 or more contractions per hour
Define sticking point:
- 1 particular angle in the ROM at which continuous smooth movements is difficult because of insufficient strength
- useful to use isometric contraction at sticking point
Progressive resistance exercise uses exercises that strengthen muscles through a contraction that overcomes some _____ resistance such as:
- fixed
- DB
- BB
- exercise machines
- tubing/banding
Progressive resistance exercises uses ______ or _______ contractions in which force is generated while the muscle is changing in ______.
- isotonic
- isodynamic
- length
Isotonic contractions can be either ______ or ______.
- concentric
- eccentric
It is possible to generate greater amounts of force against resistance with an ______ contraction, because they require a much lower level of _____ ______ activity to achieve a certain force. This means additional ____ ____ can be recruited to generate increased force.
- eccentric
- motor unit
- motor units
Oxygen use is much lower during _____ contractions, meaning they are ____ resistant to fatigue.
- eccentric
- less
The mechanical efficiency of _____ contractions can be several times higher than that of ______ contractions.
- eccentric
- concentric
Eccentric contractions are critical for _______ of limb motion, especially during ____ ____ _____ activities.
- deceleration
- high velocity dynamic
In progressive resistance exercise for max hypertrophy, it is essential for the muscle to be _____ and fatigued with what type of contraction?
- overloaded
- Both concentric and eccentric
When training specifically for the development of muscular strength, the concentric portion of exercise should require ______s, whereas the eccentric portion of the lift should require _____s.
- 1-2s
- 2-4s
It has been demonstrated that longer eccentric contractions may have a negative impact on ______ _____ movements such as the ______ ______, while shorter eccentric contractions may cause greater amounts of ______.
- dynamic explosive
- vertical jump
- soreness
Advantages and disadvantages for exercise machines:
Advantages:
- relatively safe
- simple to increase or decrease weight
Disadvantages:
- can only change weight in increments (usually 10 or 15 lbs)
- design constraints only allow single-plane motion, which limits more functional movements
Advantages and disadvantages for free weights:
Advantages:
- element of neuromuscular control
- no restricted motion
Disadvantages:
- decreased amount of weight lifted
Advantage of using elastic tubing or Thera band:
- movement can occur in multiple planes simultaneously
- more functional movement planes
Describe the issue with accommodating/variable resistance:
- amount of force necessary to move a weight through ROM changes according to the angle of pull of the contracting muscle
- greatest when angle of pull is 90 deg.
- once inertia is overcome and momentum is established, force required varies
- disadvantage of isotonic exercise: force required constantly changing throughout ROM
How have exercise machine manufacturers attempted to alleviate the problem of accommodating/variable resistance?
- changing resistive forces by using a cam in the machine’s pulley system
- cam is designed so that resistance is variable throughout the movement
- alter resistance so that the muscle can handle a greater load
- at points where joint angle or muscle length is mechanically disadvantageous, it reduces resistance
- debatable whether or not this works.
Regardless of the progressive resistance exercise technique used, the ______ ______ must dictate the specifics.
Healing process
Describe single set program:
1 set x 8-12 reps of a particular exercise at slow speed
Describe Tri-sets program:
- A group of 3 exercises for the same muscle group
- 2-4 set of each exercise with no rest in between sets
Describe multiple sets program:
2-3 warm up sets with progressively increasing resistance, followed by several sets at the same resistance.
Describe supersets program:
Either:
- 1x8-10 of several exercises for same muscle group with no rest between.
- several sets x 8-10 of 2 exercises for same muscle group with no rest between.
Describe pyramids program.
- 1x8-12 with light resistance, than increase resistance over 4-6 sets until only 1-2 reps can be performed.
- can also be reversed to go from heavy to light.
Describe split routine program.
Different muscle groups on successive days
Describe circuit training:
- can be useful for maintaining or improving levels of muscular strength or endurance in other parts of the body while healing injured body part
- series of exercise stations, move rapidly between stations
- each station involves: wt training, flexibility, calisthenics, brief aerobic exercises
- 8-12 stations, repeat circuit 3 times
It has been shown that a whole-body circuit training program can elicit both a greater _______ response and also _____ _____ gains with less ____ commitment.
- cardiorespiratory
- muscular strength
- time
Describe the DeLorme program:
- used for any level
Set 1: 50% of 10 RM x 10
Set 2: 75% of 10 RM x 10
Set 3: 100% of 10 RM x 10
Describe the Oxford technique:
- used for any level
Set 1: 100% of 10 RM x 10
Set 2: 75% of 10 RM x 10
Set 3: 50% of 10 RM x 10
Describe the McQueen technique
- differentiates between levels of rehab
Beginning-intermediate: 3x10 at 100% of 10 RM
Advanced: 4-5x2-3 at 100% of 2-3 RM.
Describe the Sanders program:
- used for advanced rehab
- based on formula that uses % BW to determine starting weights
What are the % BW starting points for the following exercises in the Sanders program?
- BB squat
- Bench press
- leg extension
- universal leg curl
- universal leg press
- upright rowing
- BB squat: 45% of BW
- Bench press: 30% of BW
- leg extension: 20% of BW
- universal leg curl: 10-15% of BW
- universal leg press: 50% of BW
- upright rowing: 20% of BW
Describe Knight’s DAPRE program:
- progressive resistance exercise
- Daily Adjusted Progressive Resistance Exercise
- allows for individual differences in rates at which patients progress
Describe the Berger adjustment technique:
- adjustable within individual limitations
- amount of weight selected should be sufficient to allow 6-8 RM in each of the 3 sets
- recovery period of 60-90s between sets. Longer = greater increases in muscle strength and hypertrophy.
- Initial selection of starting weight may require trial and error
- progression to heavier weights determined by ability to perform at least 8 RM in each of 3 sets. Increase by 10%. Still allow for at least 6 RM in each of 3 sets
For rehabilitation purposes, strengthening exercises should be performed how often? How do you set other parameters?
- daily initially
- after inflammatory phase: at least 3x/week, no more than 4x/week
- governed by injured patient’s response to the exercise
What is an isokinetic exercise?
Muscle contraction in which the length of the muscle is changing while the contraction is performed at a constant velocity.
In theory, max resistance throughout the ROM by machine is ideal.
Describe how isokinetic devices work.
- machine moves only at a preset speed regardless of force applied to it
- typically rely on hydraulic, pneumatic, mechanical pressure systems
- most machines capable of resisting concentric and eccentric
The key to isokinetic exercise is not the ______, but the …
- resistance
- speed at which resistance can be moved
In isokinetic training, it is absolutely necessary to …
Exert as much force against the resistance as possible (max effort) for max strength gains to occur.
Name some disadvantages of isokinetic strengthening programs.
- easy to cheat and not go through max effort
- cost of machines
Strength increases from slow-speed training are relatively specific to…
The velocity used in training
Strength training at faster speeds seem to produce ….
- A more generalized increase in torque values at all velocities.
- minimum hypertrophy
Slow-speed training has resulted in increased ______ _____ caused by more effective ____ ____ ____ ____.
- neuromuscular efficiency
- motor unit firing patterns
Plyometric exercise AKA
Reactive neuromuscular training
Plyometric exercises are generally incorporated into _____ stages of the rehabilitation program.
Later
Plyometric training includes ______ exercises that encompass a rapid _____ _______of a muscle, followed immediately by a rapid _______ ______ of that muscle to facilitate and develop a ______ movement over a _____ time.
- specific
- eccentric stretch
- concentric contraction
- explosive
- short
In Plyometric exercise, the greater the stretch put on the muscle from resisting ______ immediately before the concentric contraction, the greater the _______.
- length
- resistance the muscle can overcome
Plyometrics emphasize the _____ of the ______ phase. The _____ of stretch is more critical than the ______ of the stretch.
- speed
- eccentric
- magnitude
An advantage to using Plyometric exercises is that they can help to develop ______ control in ______ movements.
- eccentric
- dynamic
Plyometrics tend to place a great deal of stress on the ______ system.
Musculoskeletal
Plyometric exercises must be _____ _____ and specific to one’s _____, _____, ______ ______, and _____ _____.
- technically correct
- age
- activity
- physical development
- skill development
Most BW exercises require the individual to ______ the body or move the total body against the ______ ____ _____.
- support
- force of gravity
BW exercises are often used in _____ strength training.
Functional
To be considered maximally effective, the isotonic BW exercise must be performed in full _____.
ROM
Parameters for most BW exercises:
2-3x10+
Some free exercises use an _____ or _____ phase instead of a full ROM. When the exercise produces max _____ _____, it is held for ____s and repeated ____ times.
- isometric
- hold
- musBWcle tension
- 6-10s
- 1-3x
A _____ core stabilization training program should be a fundamental component of all comprehensive _____ as well as _______ ______ programs.
- dynamic
- strengthening
- injury rehab
The core is defined as the _______ complex and is where the ______ ___ _____ is located, and where all movement ______.
- lumbo-pelvic-hip complex
- centre of gravity
- begins
A core stabilization strengthening program can help to improve:
- dynamic postural control
- muscular balance and joint movement around the lumbo-pelvic-hip complex
- expression of dynamic functional strength
- neuromuscular efficiency
Collectively, a core stabilization strengthening program contributes to optimal ______, ______, and _____ stabilization of the entire ____ ____ during _____ movements.
- acceleration
- deceleration
- dynamic
- kinetic chain
- functional
The body’s stabilization system has to be functioning optimally to effectively use the prime movers’ ….
- strength
- power
- neuromuscular control
- muscular endurance
A weak core is a fundamental problem of _____ _____ that leads to injury.
Inefficient movements
Kinetic chain:
Anatomical functional relationships that exist in the UE and LE.
OKC:
- open kinetic chain
- when the foot or hand is not in contact with the ground or some other surface
CKC:
- closed kinetic chain
- the foot or hand is WB
Movements of the more _____ anatomical segments are affected by these open vs closed kinetic chain positions.
Proximal
In CKC, the forces begin at the ______ and work their way up through each _____. Forces must be _____ by various tissues and anatomical structures, rather than simply _____ as would occur in an open chain.
- ground
- joint
- absorbed
- dissipating
Most functional activities, particularly those of the LE involve some aspect of _____.
WB
_____ kinetic chain strengthening exercises are more functional than _____ kinetic chain exercises.
- closed
- open
Rehabilitative exercises should be incorporated that emphasize strengthening of the entire _____ ____ rather than an isolated body segment.
Kinetic chain
It is generally accepted that when resistance training for strength, _____ weights with a _____ number of repetitions should be used.
- heavier
- lower
It is generally accepted that when resistance training for endurance, ____ weights with a _____ number of repetitions should be used.
- lighter
- greater
Parameters for muscular endurance training:
3x10-15
Physiologic differences between males and females in strength training:
- less bulk for females d/t decreased testosterone
- both see rapid gains in strength during initial phase due to improved neuromuscular efficiency. Females plateau and see minimal improvement in continuing training. Males: continue to increase with appropriate training
- differences in strength seen in relation to BW minus fat. Reduced strength-to-BW ratio in women due to increased % of body fat.
If properly supervised adolescents can use resistance training to:
- improve strength, power, endurance, balance, and proprioceptive
- develop a positive body image
- improve sports performance
- prevent injuries
A prepubescent child can experience gains in levels of muscle strength without ____.
Hypertrophy
What is important to remember when using resistance exercises in a rehabilitation program for an injured adolescent?
- close supervision
- proper instruction
- appropriate modification of progression and intensity based on the extent of physical maturation
The goal of resistance training in a rehabilitation program:
- Regain or increase the strength of a specific muscle that has been injured
- increase the efficiency of movement about a given joint
