define muscle endurance
ability to perform repetitive or sustained activities for prolonged periods
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| Term | Definition |
|---|---|
| define muscle endurance | ability to perform repetitive or sustained activities for prolonged periods |
| what is cardiopulmonary endurance | whole-body dynamic activities while walking, cycling, swimming |
| what is local muscle endurance | muscles' ability to repeatedly contract, sustain tension, and resist fatigue |
| characteristics of endurance training | high reps, low intensity, long duration |
| why is endurance training often better for impaired muscle performance | less joint reaction force, less irritation, more comfortable |
| what is the overload principle | muscle must be challenged with a load greater than it is accustomed to |
| how do you apply overload | increase intensity or volume |
| what is the SAID principle | training adaptations are specific to the demands placed on the muscle |
| example of SAID principle for power training | increase work demands + decrease time -> explosive movements |
| what is specificity of training | training effects are specific to mode, velocity, joint position, and movement pattern |
| example of specificity for stair climbing | use weight-bearing concentric + eccentric training at functional speed |
| what is transfer of training (carry over effect) | strength training may moderately improve endurance; endurance training does not improve strength |
| what is the reversibility principle | training effects are not permanent; gains decline without continued training |
| when does detraining begin | within 1-2 weeks after stopping exercise |
| what is the role of actin in the sarcomere | thin filament anchored to Z-line; contains binding sites for myosin |
| what is the role of myosin | thick filament with heads that form cross-bridges; ATP allows detachment and hydrolysis "cocks" the head |
| what does strength testing assess at the sarcomere level | the ability of sarcomeres to generate tension |
| what does stretching do at the sarcomere level | lengthens sarcomeres and changes actin-myosin overlap |
| define concentric contraction | sarcomeres shorten under load; builds strength and power |
| define eccentric contraction | sarcomeres lengthen under load; builds mass and control |
| define isometric contraction | sarcomeres maintain length under tension; improves stability and endurance |
| what triggers muscle contraction at the neuromuscular junction | ACh release -> calcium release -> contraction |
| what is a motor unit | a motor neuron and all muscle fibers it innervates |
| what is the recruitment order of muscle fibers | type I -> type IIa -> type IIb |
| what do small motor units control | fine motor control (eyes, hand intrinsics) |
| what do large motor units control | powerful force production (glutes, quads) |
| key characteristics of Type I fibers | high mitochondria, high capillaries, fatigue-resistant, small diameter |
| what is the function of Type I fibers | postural control, endurance, stability |
| clinical relevance of Type I weakness | poor postural endurance; common in chronic lower back pain |
| key characteristics of Type II fibers | large diameter, high force, fatigue quickly, anaerobic |
| function of Type II fibers | power, speed, explosive movement |
| clinical relevance of Type II atrophy | atrophy quickly with immobilization, important in rehab |
| characteristics of Type IIa fibers | fast, moderate fatigue resistance, mixed metabolism |
| why are Type IIa fibers important in rehab | adaptable toward endurance or power depending on training |
| characteristics of Type IIb fibers | fastest, largest, highest force, very low fatigue ressitance |
| function of Type IIb fibers | maximal-intensity, explosive, short-duration movements |
| what physiological changes occur with strengthening | increased fiber size, neural drive, motor unit recruitment, bone density |
| what is Wolff's Law | bone remodels according to the loads placed on it |
| what is the overload principle | load must exceed the muscles metabolic capacity to improve performance |
| how do you overload for strength | increase load progressively |
| how do you overload for endurance | increase reps, duration, or time under tension |
| what is a repetition maximum | greatest amount of weight a muscle can move once through full ROM |
| what % of 1RM does the average adult train at | 75% of 1RM |
| what is the standard strength protocol | 3 sets x 10 reps with load causing fatigue |
| what is the standard endurance protocol | submax load, 3-5 sets, 40-50 reps OR long sustained holds |
| what is an isometric exercise | static contraction without joint movement |
| what is muscle setting | low-intensity isometrics for relaxation, circulation, and reducing spasm |
| what is stabilization isometrics | isometric contraction in weight-bearing to improve joint/postural stability |
| what are multiple-angle isometrics | resistance applied at multiple joint angle to improve strength through ROM |
| standard isometric protocol | 7-10 reps, 3-5 sets, 5-7s holds |
| what is isotonic exercise | muscle changes length while exerting constant force |
| what are the two isotonic contraction types | concentric (accelerate) and eccentric (decelerate) |
| what produces more force | concentric or eccentric |
| what is isokinetic exercise | movement at constant velocity; machine controls speed |
| what defines open-chain exercise | distal segment moves; non-weight bearing; isolated muscle activation |
| what defines closed-chain exercise | distal segment fixed; weight-bearing; multi-muscle activation |
| key precautions for strengthening | pain-free range, avoid breath-holding, avoid ballistic movement, progress gradually |
| what is DOMS | delayed onset muscle soreness 12-24 hours after exercise; peaks 48-72 hours |
| absolute contraindications to strengthening | unstable joints, fragile tissue, inflammation, major cardiopulmonary disaese |
| what is aerobic exercise training | CR endurance training using oxygen-dependent metabolism |
| what is the Karvonen formula | exercise heart rate = HR rest + 60-70% (HRmax-HRrest) |
| standard aerobic training protocol | 5-10 min warm-up, 20-30 min aerobic, 5-10min, frequency |
| what are the major effects of disuse on soft tissue | loss of mobility/strength, decreased ROM, altered neuromuscular control, increased stiffness |
| define contracture | adaptive shortening of musculotendinous & soft tissue -> restricted ROM |
| what causes a myogenic contracture | adaptive shortening of musculotendinous unit with no underlying pathology |
| how is a myogenic contracture managed | stretching - static, PNF, prolonged low-load |
| what causes a pseudomyostatic contracture | CNS lesions or prolonged spasm/guarding |
| what are key features of pseudomyostatic contracture | constant contraction, excessive resistance to passive stretch |
| how is pseudomyostatic contracture managed | neuromuscular inhibition (hold-relax, contract-relax, rhythmic rotation) |
| what causes arthrogenic/periarticular contracture | intra-articular pathology (adhesiosn, synovial thickening, effusion, osteophytes) |
| how is arthrogenic contracture managed | joint mobilization, stretching, treating underlying pathology |
| what causes fibrotic/irreversible contracture | prolonged immobilization, severe trauma, chronic inflammation |
| what are features of fibrotic contracture | dense adhesions, permanent loss of extensibility, severe ROM limitations |
| how is fibrotic contracture managed | stretching minimally helpful; often requires surgery |
| define hypotrophy vs atrophy | hypotrophy |
| what causes atrophy | disuse, immobilization, pain-avoidance, neurological impairment |
| consequences of atrophy | decreased force production & endurance, altered movement, increased injury risk |
| what is decreased neurological activity | reduced neural drive -> decreased activation & coordination |
| effects of decreased neural activity | few signals, delayed stabilizer recruitment, reliance on compensations |
| define PROM | movement by an external force only; no voluntary contraction |
| indications for PROM | acute inflammation, post-surgery, paralysis, bed rest |
| goals of PROM | maintain mobility, minimize contractures, enhance synovial movement, decreased pain |
| limitations of PROM | cannot prevent atrophy, increase strength, or improve circulation like active movement |
| PROM contraindications | unstable fracture, unhealed incision, acute muscle tear, DVT |
| PROM protocol | slow, pain-free, support limb, avoid forcing end-range |
| define AFROM | movement through voluntary contraction within available range |
| indications for AFROM | aerobic conditioning, postural strengthening, maintaining mobility above/below immobilized joints |
| define AAROM | assisted movement when client cannot complete range independently |
| goals of AFROM | maintain elasticity, provide sensory feedback, stimulate bone/joint tissue, increase circulation, prevent thrombus |
| limitations of AFROM/AAROM | cannot increase strength of healthy muscle or develop advanced coordination |
| contraindications for AFROM/AAROM/ARROM | acute inflammation, unstable fracture, post-surgery restrictions, severe cardiopulmonary disease, DVT |
| ROM progression order | AAROM -> AFROM -> ARROM |
| what must be documented for PROM | joints moved, range achieved, client response, end feel, rationale |
| what must be documented for AFROM/AAROM/ARROM | type of ROM, quality, range, strength limits, tolerance, rationale |