Strength Exercise PDF

Strength Exercise Therapeutic Exercise 1 What is Strength Training? Synonymous with resistance training Involves muscles working against a Body weight, free weights, weight load (weight or resistance) machines, resistance bands… Considered a form of anaerobic...

Strength Exercise Therapeutic Exercise 1 What is Strength Training? Synonymous with resistance training Involves muscles working against a Body weight, free weights, weight load (weight or resistance) machines, resistance bands… Considered a form of anaerobic exercise- dominance of pathways that synthesise ATP without O2 Strength Exercise: Basic Concepts Strength… what is it? The ability of a muscle, or muscle group, to assert force against a load In strength Amount of exercise, force is resistance/ generated by weight applied to muscles a movement “Neuromuscular capacity to initiate, accelerate, decelerate, stop, and/or change direction of a load internal and external to the organism” How do we Produce Strength? By producing a muscular contraction The arrival of an action potential which causes the muscle to shorten/ lengthen/ maintain position in response to the load Concentric- Eccentric- Isometric The Production of a Muscular Contraction A motor neuron carries an action potential to the neuromuscular junction of a muscle fibre, releasing Ach, depolarising the muscle fibre Calcium influx causes myosin binding sites to be exposed Myosin heads bind to the actin and pull the actin towards the M line One motor neuron supplies multiple muscle fibres, this is called a motor unit Motor neuron Motor unit Myosin heads Myosin binding Neuromuscular sites Actin junction  Number of recruited motor units, and recruitment co-ordination Size of muscle (primarily fibre diameter) and connective tissue quality Local Factors Muscle fibre type Affecting Force of Muscle Muscle fibre orientation Contraction Contraction type Sarcomere length at initiation Fatigue: central and peripheral  Size of muscle (primarily fibre thickness) and connective tissue quality Increasing Number of recruited motor units generation and improving force transmission Muscle fibre orientation Power determined by density of fibres within a muscle. Range on length. Sarcomere length at initiation  Local Factors NAME TYPE I (Red) Slow oxidative TYPE IIA Fast oxidative TYPE IIB/X (White) Fast glycolytic Affecting Force of Diameter Small glycolytic Intermediate Large Muscle Contraction ATP synthesis Aerobic Aerobic and ATP-PC and glycolytic pathway glycolytic Velocity of Slow Quick Quick Types of muscle fibres: Type I, IIA, Contraction IIB Strength of Low High High Contraction High maximum forces Fatigue Response High Resistance Mid Resistance Low Resistance correlated to high proportion of Aerobic Capacity High Moderate Low fast oxidative and fast glycolytic Anaerobic Capacity Low Moderate High fibres Predominant stores Myoglobin, Myoglobin, Glycogen and PC Physiology optimised for and vascularity mitochondria and mitochondria and anaerobic energy pathways to capillaries capillaries allow fast production of ATP 1. Local Factors Affecting Force of Muscle Contraction: Fatigue Involuntary, inevitable and reversible decrease in the force applied after an effort" (Enoka & Stuart, 1992) Central Fatigue Decrease in voluntary activation related to: decreased frequency and synchronization of motor neurones and decreased drive from motor cortex Affected by: sleep deprivation, task fatigue, anxiety, stress, subjective fatigue perception, serotonin increase V dopamine decrease2 The Physiology Basis of Neuromuscular Fatigue during High Intensity Exercise 3 Local Factors Affecting Force of Muscle Contraction: Fatigue Peripheral Fatigue Decrease in contractile strength of muscle fibres due to: impairment of cross-bridge action Affected by: metabolite accumulation and ATP synthesis reduction- pyruvate and hydrogen increase, glycogen depletion, acidosis  Isometric Local Factors Affecting Isotonic: Concentric- Eccentric Force of Muscle Antagonist, agonist, and synergists Contraction: Motor Unit Intramuscular Coordination (same muscle) recruitment co-ordination Intermuscular Coordination( between muscles) Intramuscular Co-ordination Intermuscular Co-ordination Synchronized recruitment of motor units during the Coordination between antagonists, agonists, and execution of a muscle contraction. synergists to produce an efficient and effective action. Strength Exercise: Definitions Rate of Perceived Exertion Rep Max (RM) Repetitions in reserve (RIR) Character of effort (RPE) The maximum amount of weight that a person can lift in a given number of repetitions e.g., 1RM, 5RM A measure of the level of exertion a person feels during physical activity The remaining number of repetitions a person thinks they are able to do before failure Relationship between effort and velocity of movement Strength 5. The ability to change from an eccentric muscular contraction to a concentric one (stretch shortening cycle) Definitions 6. The enlargement of an organ because of an increase in the size of a cell e.g., 1. Maximum strength of muscle fibre 2. Muscular endurance 2. The ability of a muscle (/group of) to repeatedly contract against a force for an extended period of time 3. Muscle power 4. Description of the ability to produce a force in the shortest unit of time possible (rate of force development) 4. Explosive strength 1. Maximum force a muscle can apply against a load in a single contraction 5. Reactive strength 6. Hypertrophy 3. The peak sum of force and speed (force x velocity)  Force / Velocity Relationship Greater load can be taken in an eccentric contraction V concentric contraction Eccentric contraction Isometric contraction Concentric contraction Velocity = 0 When force increases, When force increases, velocity velocity increases. decreases. Imagine lowering a loaded Imagine raising weight in a bench press- the greater the squat- the greater the weight, load, the faster it lowers the slower it raises Power: The Relationship between Force and Velocity Power = force x velocity Peak power occurs at submaximal speed and load Variation depending on movement performed Power can be a determining factor in both sport and older adult independence4  The time taken to reach required force Explosive Important in movements/activities Strength: The requiring speed Linked to muscle fibre type and efficiency Rate of Force of neural drive Development Correlates to reactive strength (stretch shortening cycle) Strength Exercise: Effects of Strength Exercise  Changes in response to training programme Adaptation Changes reliant on overload A load is applied that exceeds the habitual load Adaptation in Response Loading and metabolic demands exceed the to Strength Maladaptation adaptive potential Prescription not sufficiently progressive Training Maintenance of the adaptations achieved in Retention response to a training programme Reversal of adaptation in response to a Detraining decrease in the training volume Adaptation in Response to Muscle fibre adaptation towards type IIa/type IIx Strength Muscle fibre hypertrophy Training Increased glycogen and PC reserves Increased enzyme activity and efficiency for ATP synthesis Optimized motor unit recruitment (intramuscular) Optimized intermuscular co-ordination Efficient force transfer from connective tissue adaptation Performance Load Performance Load Performance Level Level Level Load stimulus stimulus stimulus Time Time Time Training frequency optimised for Frequency allows for recovery, but Too much frequency leading to progression supercompensation not utilised decrease in performance Factors Affecting Adaptation: Frequency The Phenomenon of Supercompensation Factors Affecting 1.Initial Exercise Stress: temporary Adaptation: Frequency decrease in performance due to the stress of exercise. 2.Recovery Phase: The body begins to repair and rebuild muscle tissues and energy stores. 3.Supercompensation Phase: The body adapts by increasing its capacity beyond the initial level, leading to enhanced 5. strength and performance. 4.Return to Baseline: If no further training 5. stimulus is applied, the body will gradually return to its baseline performance level. Factors Affecting Adaptation: Intensity If habitual load is provided, then adaptation stabilises If habitual load is lowered, then adaptations reverse to match requirements The greater the person is ‘trained’, the harder it is to achieve further adaptation Factors Affecting Adaptation: Other Influencing Factors Aside from strength training prescription, other factors influence adaptation Stress Genetic ability to respond6 and genetic ceiling Factors Affecting Adaptation: Specificity Power Explosiveness Maximum strength Identify required strength characteristics and ensure training specific to this Strength Exercise: Assessment What is the purpose of the test? Assess the patient against the norms of a similar population? To aid reasoning in “return to play”? To provide an outcome measure? Look for differences? Determine limiting factor to an activity?  Strength Assessment Functional Classification Quantifying e.g., sit to stand e.g., Oxford scale of muscle power e.g., grip strength dynamometer Relevant in patients with objectives Quick, inexpensive, but does not Quantitative measures aiming to based on ADLs/functional truly quantify provide precision and reliability in independence testing Static A muscle group Isometric forces normally Time/ weight/ force Dynamic Involves more muscle groups and neuromuscular challenge ROM reference always the same 1RM (RIR-RPE concurrently measured)  Assessment: Maximum Strength Direct and indirect (estimation) approach Common factors such as warm up and progressive sets Direct Approach Indirect Approach Warm-up 10 minutes, increase HR, mobility, action without load Progression 2-3 sets (5 reps) 50/70% 2-3 sets progressing weight (individualised) Approximation 3 sets 80% After rest, try for 1-7RM and compare to calculator/ Epley formula Final Try for new 1RM +/- Test if 1RM is correct Assessment: Maximum Strength - Direct approach: use previous 1RM - For indirect approach: progressive sets finish where a weight can be estimated for a final low RM attempt- use RIR and RPE to estimate final set! Both methods should respect rest time 3-5 Epley´s formula: 1RM= weight lifter x ( number of reps ) 30 mins between sets  Assessment: Maximum Strength Single plane of movement Standardized technique  Symptoms Confidence Advantages and disadvantages of direct V indirect method of 1RM testing? Validity Purpose of test Assessment: Grip Strength Test Arm supported with your elbow at 90-degree flexion Squeeze the dynamometer as hard as possible Apply grip force in a smooth motion. Avoid jerking (3-5secs/until needle doesn’t move) Repeat 3 times total, with standardized rest Assessment: Grip Strength Test Remember- each test has a purpose Hand grip strength has been used to investigate scores with outcomes Level of dependence of Hand grip strength post hip patient at D/C, and 6 months fracture post D/C Low measures correlate to higher levels of dependence post hip 8. fracture Assessment: Power Tests often combine elements of power, reactive strength, and explosiveness Long (broad) jump Vertical jump Hop distance X3 hope distance 6m hop time Drop jump Assessment: Movement Analysis Quantity of movement (repetitions, distance, fatigue, rest time) Quality of movement What is the limiting factor? Patient effort? Understanding of task? Pain? Ideas Range of movement? Practice? Fatigue? Force-Velocity Profiling Used for performance testing in sports where explosiveness is required E.g., sprinting, high jump, shot put An optimal force-velocity curve is calculated which is specific for the activity. The athlete is tested and plotted against the curve to determine if they are force or velocity dominant. Their strength training programme can then be designed around these results  Assessment: Muscular Endurance How long can the patient maintain a contraction against an equal load, or how many repetitions before failure? Timed/ time limit/ rhythm 7. Single leg heel raise 1/sec Assessment: Muscular Endurance Wall sit- single leg Strength Exercise: Designing an Exercise Programme  Patient´s understanding of situation/ perceived problem Basis for Patient´s objectives Programme Assessment of relevant factors that may contribute Prescription to perceived problem/ actual state Programme design: ensure individualised and based on patient objectives and assessment Assessment tests, if Re-evaluation of the perceived problem/ actual state standardised, are outcome measures Programme: Patient Assessment and Objectives Short term and long Previous experiences term objectives Beliefs around strength training Motivators Co-morbidities Barriers Frequency How often? Intensity Programme: How hard? FITT-VP Time Prescription How long? Method Type What exercises? Volume FIT totals Progression When and how to progress? Programme: Frequency 2-3 weekly sessions 48 h break between sessions (non-consecutive) Sessions focused on global work or separate groups Remember- frequency has an effect on adaptation! Performance Load Performance Load Performance Level Level Level Load stimulus stimulus stimulus Time Time Time Training frequency optimised for progression Frequency allows for recovery, but Too much frequency leading to decrease in supercompensation not utilised performance Programme: Intensity 1 RM for strength gain: RPE for strength gain: Start with values close Start with RPE approx. 5 to 50% 1RM. Ideal= values of >6 when Ideal= values between finishing set 50 and 85% RM. Respect rest time: Common measures of intensity RIR for strength gain: in strength exercise: Ideal=