Unit 5: Resistance

Why use a repetition maximum?

1. Documents a baseline measurement of dynamic strength to which improvements can be compared 2. Identifies initial exercise load to be used for a specified number of repetitions

How many reps do you do with 90% of 1-RM?

4-5 repetitions (Although some say you can only do 3)

What is resistance?

Active exercise in which a muscle contraction is resisted by an outside force: i.e. gravity, manual or mechanical force.

Concentric/ Eccentric? Which muscle contractions are more efficient metabolically and generate less fatigue?

Eccentric Contrations

Overload principle

Muscles performance improves only if the muscle is challenged to perform at a level greater than that to which it is accustomed. EX: Once something's easy, make it harder!

Isometric contraction

Static muscle contraction that produces a constant force without an appreciable change in the length of the muscle and without visible joint motion.

Delorme Regimen

The Delorme technique builds a warm-up period into the protocol. 10 Reps @ 50% of the 10-RM 10 Reps @ 75% of the 10-RM 10 Reps @ 100% of the 10-RM

Endurance

The ability to perform low-intensity, repetitive, or sustained activities over a prolonged period of time. -- Uses slow-twitch muscle fibers (Type I) -- Improved with low resistance and high repetitions. --For many pts with impaired muscle performance, endurance training has a more positive impact on improving function than strength training.

Intensity of exercise in a resistance training program

The amount of resistance (weight) imposed on the contracting muscle during each repetition of an exercise.

Power

The combination of strength and speed of a movement. The main focus of power training is to maximize strength in the smallest amount of time.

Eccentric contraction

The elongation of the muscle. Dynamic loading of a muscle beyond its force-producing capacity, causing physical lengthening of the muscle as it attempts to control the load, as when lowering a weight.

Repetition Maximum (RM)

The greatest amount of weight a muscle can move through the full range of motion a specific number of times in a load-resisting exercise routine.

Strength

The greatest measurable force that can be exerted by a muscle to overcome resistance during a single, maximum effort. --Uses fast-twitch muscle fibers (Type II) -- Strength is improved with high resistance and low repetitions.

Frequency in a resistance program

The number of exercise sessions per day or per week.

What is a Gravity minimized Position?

The position between gravity eliminated and against-gravity. Note: Not all muscle actions have a gravity minimized position.

Concentric contraction

The shortening of the muscle. An external force (resistance) is overcome, as when lifting a weight.

Volume of exercise

The summation of the total number of repetitions and sets of a particular exercise during a single exercise session.

Duration of exercise

The total number of weeks or months during which a resistance program is carried out, this is typically determined by the PT.

The SAID Principle (Specific Adaptation of Imposed Demands)

Tissues remodel in accordance to the stresses placed upon them. Based on Wolff's Law: Body systems adapt over time to the stresses placed upon them. Ex: You get what you train for. For a marathon, run long distances!

Precautions of repetition maximum

Use of a 1-RM as a baseline measurement of dynamic strength is inappropriate for some pt populations because it requires one maximum effort. Pts with: joint impairments, recovering from or at risk for soft tissue injury, known/ at risk for osteoporosis or cardiovascular pathology.

Open Chain Exercise

When a non weight bearing position is assumed and the distal segment (foot and hand) moves freely during exercise, the term is open-chain.

Closed Chain Exercise

When weight bearing position is assumed and the body moves over a fixed distal segment, the term is closed-chain.

Rationale for use of Concentric and Eccentric Exercise:

* Concentric muscle contractions accelerate body segments *Eccentric muscle contractions decelerate body segments (e.g., during sudden changes of direction or momentum.) and act as shock absorption during high-impact activities.

Why use Open Chain vs. Closed Chain?

--CCE are thought to be "more functional" than OCE --OCE target specifically one movement at a joint. --CCE target synergistic movement patterns, mimic the firing patterns of functional tasks. --Studies suggest CCE cause less shear forces on a joint than the OCE.

Signs and symptoms of muscle fatigue:

1. An uncomfortable sensation within the muscle, even pain and cramping. 2. Tremulousness in the contracting muscle. 3. Active movements are jerky, not smooth. 4. Inability to complete the movement pattern through the full ROM during dynamic exercise against the same level of resistance. 5. Use of substitute motions, (incorrect movement patterns), to complete the movement pattern. 6. Inability to continue low-intensity physical activity. 7. Decline in peak torque during isokinetic testing.

Sequence for exercises program:

1. Large muscle groups should be exercised before small muscle groups 2. Multi-joint exercises should be performed before single-joint exercises 3. Higher intensity exercises should be performed before lower intensity exercises.

Rationale for using Isometric Exercise

1. MINIMIZES MUSCLE ATROPHY when joint movement is not possible (casts, splints, skeletal traction) 2. To facilitate muscle activity in order to begin to re-establish NEUROMUSCULAR CONTROL but protect healing tissues when joint movement is not advisable after soft tissue injury or surgery 3. To develop POSTURAL/ JOINT STABILITY 4. To improve MUSCLE STRENGTH when use of dynamic resistance exercise could compromise joint integrity or cause joint pain 5. To develop STATIC muscle strength at particular points in the ROM consistent with SPECIFIC TASK-RELATED NEEDS

What parameters can be modified with Progressive Resistance Exercise (PRE).

1. patient position, 2. type of resistance 3. lever arm, 4. repetitions, 5. sets, 6. contraction duration (for isometrics) 7. frequency per day or week.

How many reps do you do with 75% of 1-RM?

10 repetitions

How many reps do you do with 60% of 1-RM?

15 repetitions

What is a typical PRE programs that would produce training-induced strength gains?

2 to 3 sets of a 6 to 12 repetitions.

Fatigue

A diminished response of a muscle to a repeated stimulus. *A muscle needs to be exercised to fatigue in order to improve and gain strength. *The signs of fatigue are looked for at the end of the repetitions that have been prescribed, not at the beginning.

Progressive Resistance Exercise (PRE)

A system of dynamic resistance training in which constant external load is applied to the contracting muscle by some mechanical means and incrementally increased. The Repetition Maximum (RM) is used as the basis for determining and progressing the resistance.

Strength training

A systematic procedure of a muscle or muscle group lifting, lowering, or controlling heavy loads (resistance) for a relatively low number of repetitions or over a short period of time.

Specificity of Training

Adaptive effects of training such as improved strength and endurance are highly task-specific. Therefore, exercises in a training program should mimic the anticipated function. Ex: cross training to develop strength or endurance. Swimmers don't just swim.

How much resistance do you use?

After a RM is ascertained, the exercise load (amount of resistance) to be used at the initiation of resistance training is calculated as a percentage of the 1-RM. --40-70% is average for healthy, untrained adult --30-50% for elderly or children --very high (>80%) for those that are highly trained in order to achieve training-induced adaptations.

Aerobic Exercise-

Associated with low-intensity, repetitive exercise of large muscle groups performed over an extended period of time. This mode of exercise primarily increases muscular and cardiopulmonary endurance.

Concentric/ Eccentric? Which are commonly used in the rehabilitation process due to the frequent occurrence in ADL's?

Concentric contractions

Integration of rest into Exercise:

Dependent upon the intensity and volume of exercise. Higher intensity= longer the rest interval, > 3 minutes Moderate intensity, = 2-3 minutes Low intensity= shorter rest period

Oxford Regimen

Diminishes the resistance as the muscle fatigues. 10 Reps @ 100% of the 10-RM 10 Reps @ 75% of the 10-RM 10 Reps @ 50% of the 10-RM

Dynamic Exercise/ Constant External Resistance (DCER) (also known as isotonic):

Dynamic exercise against constant external resistance. Limb moves through a ROM against a constant external load. Includes: concentric and eccentric muscle contractions

Concentric/ Eccentric? Which can controll greater loads? can be controlled with eccentric rather than concentric exercise

Eccentric exercise

Concentric/ Eccentric? Adaptations associated with which training are more mode and velocity specific?

Eccentric training

Delayed-Onset Muscle Soreness (DOMS)

Exercise induced muscle tenderness or stiffness that occurs 24 to 48 hours after vigorous exercise.

Concentric/ Eccentric? When is there is greater incidence and severity of delayed-onset muscle soreness?

Following unaccustomed, high-intensity eccentric exercise

Type II (phasic, fast-twitch) muscle fibers

Generate a great amount of tension in a short period of time. Geared towards anaerobic metabolic activity and tend to fatigue quickly.

Type I (tonic, slow-twitch) muscle fibers

Generate a low level of muscle tension but can sustain the contraction for a long period of time. Geared towards aerobic metabolism and are very slow to fatigue.

Reversibility Principle

If you don't use it, you lose it. Adaptive effects of training such as improved strength and endurance are transient unless maintained by functional activities or a regular exercise program. While rest periods are necessary for recovery, extended rest intervals reduce physical fitness.

Anaerobic Exercise-

Involves high-intensity (near maximal) exercise carried out for a very few number of repetitions because muscles rapidly fatigue. Strengthening exercises fall in this category.

Concentric/ Eccentric? Which caused greater Training-induced gains in muscle strength and mass?

Maximum-effort eccentric training