Exercise therapy

In short

Exercise therapy is the planned, graded use of body movement, posture and physical activity to restore range of motion, strength, endurance, flexibility, balance, coordination and function, and to prevent further impairment. It is the core, drug-free tool of physiotherapy practice and the reason a physiotherapist is consulted for orthopaedic, neurological, cardiorespiratory, obstetric, paediatric and sports conditions. In BPT it is examined in its own paper (Exercise Therapy, usually second/third year) and again in clinical subjects, viva and practicals — goniometry, manual muscle testing (MMT), exercise prescription and crutch measurement are the standard practical stations. Employers who test it in interviews and demonstrations include AIIMS, PGIMER, ESIC and state health services, Apollo, Fortis, Max, Manipal, Narayana Health, HOSMAT, Sancheti, Portea and HealthCare atHOME, plus corporate ergonomics and sports teams.

Explained

Foundations: principles, mechanics and planes

• Definition: movement prescribed as treatment — active or passive, assisted or resisted — to correct an impairment, improve musculoskeletal or cardiorespiratory function, or maintain a state of well-being.
• Aims: relieve pain and spasm, gain or maintain range of motion (ROM), increase muscle strength/power/endurance, re-educate muscle and movement, improve balance, coordination and gait, raise cardiorespiratory capacity, promote relaxation and functional independence.
• Training principles: overload (a stimulus above habitual demand), progression, specificity (SAID — Specific Adaptation to Imposed Demands), reversibility (gains lost in 2–3 weeks of inactivity), individuality, recovery, and transfer of training to function.
• Anatomical planes and axes: sagittal plane/frontal (coronal) axis — flexion, extension; frontal plane/sagittal axis — abduction, adduction; transverse plane/vertical axis — rotation. A joint's degrees of freedom decide which planes are possible.
• Mechanics used daily: levers (joint = fulcrum, muscle pull = effort, body segment + load = resistance; most body levers are third class — poor mechanical advantage, good speed/range), torque, angle of pull, gravity (assisting, counterbalanced, or resisting), pulleys (a single fixed pulley only changes the direction of the pull), springs (resistance proportional to stretch) and pendulum action.
• Group action of muscles: agonist (prime mover), antagonist (relaxes/controls), synergist, fixator. Co-contraction stabilises; reciprocal inhibition allows smooth motion.

Starting positions, measurement and assessment

• Fundamental starting positions (5): standing, kneeling, sitting, lying, hanging. Each has derived positions altering base, centre of gravity and muscle work — e.g. from lying: crook lying, half lying, prone lying, side lying, inclined lying; from sitting: long sitting, crook sitting, stride sitting, side sitting.
• Stability of a position increases with a larger base, a lower centre of gravity and a line of gravity falling well within the base — the basis of choosing a position for a weak or ataxic patient.
• Goniometry: universal goniometer — fulcrum on the joint axis, stationary arm along the proximal segment, movable arm along the distal segment. Record as start–end (e.g. knee 0°–130°, or 10°–130° if there is a 10° extension lag). Use the ISOM (0–180°) notation; inclinometer/tape for spine (modified Schober), goniometric apps and the BROM/CROM for cervical spine.
• Normal ROM (approximate, adult): shoulder flexion 0–180°, abduction 0–180°, elbow 0–145°, wrist flexion 0–80°/extension 0–70°, hip flexion 0–120°, extension 0–30°, knee 0–135°, ankle dorsiflexion 0–20°/plantarflexion 0–50°.
• End-feel: bony (elbow extension), capsular/firm (hip rotation), soft tissue approximation (knee flexion); abnormal end-feels — springy block (meniscus), empty (pain), spasm.
• Manual muscle testing (MMT), Oxford/MRC 0–5 scale: 0 no contraction; 1 flicker; 2 full ROM with gravity eliminated; 3 full ROM against gravity; 4 full ROM against gravity plus moderate resistance; 5 normal resistance. Plus/minus grades refine it (3+, 4−). Limitations: subjective, poor sensitivity above grade 4, invalid with spasticity (use Modified Ashworth instead) and in children under ~5.
• Other assessment: limb girth (muscle bulk), limb length, posture and gait analysis, functional scales (Barthel Index, FIM), pain VAS/NPRS, Berg Balance Scale, Timed Up and Go, 6-minute walk test.

Classification of therapeutic movement

• Passive movements — produced by an external force, patient's muscles inactive.
  • *Relaxed passive movements:* slow, rhythmic, within available range — maintain ROM, circulation and tissue extensibility in paralysis or coma.
  • *Passive mobilisation / accessory movements:* graded oscillations to joint play (Maitland grades I–IV; Kaltenborn I–III).
  • *Forced passive movement and manipulation:* under anaesthesia or by a skilled therapist to break adhesions — high risk, strict indications.
  • *Sustained passive stretching:* slow, low-load, long-duration (20–30 s up to several minutes) to lengthen shortened tissue; serial casting/splinting for contracture.
  • *Continuous passive motion (CPM):* machine-driven, used after total knee arthroplasty and arthrolysis.
• Active movements — produced by the patient's own muscle contraction.
  • *Assisted (active-assisted):* therapist, gravity, sling suspension, hydrotherapy buoyancy or the other limb supplies the deficit — for grades 1–2.
  • *Free (active) exercise:* performed against gravity only — grade 3; graded by speed, range, repetition, leverage and starting position.
  • *Assisted-resisted:* assistance in the weak part of range, resistance where the muscle is strong.
  • *Resisted exercise:* against manual, weight, spring, elastic (TheraBand), pulley, hydraulic or isokinetic resistance — grades 4–5.
• Types of muscle work: isometric/static (tension without length change — safe post-operatively and in immobilisation; strength gain is angle-specific, ±20°); isotonic/dynamic — concentric (shortening) and eccentric (lengthening, highest force, most delayed-onset muscle soreness, used in tendinopathy as Alfredson's protocol); isokinetic (constant angular velocity, accommodating resistance, needs a dynamometer such as Biodex/Cybex).
• Derived forms: pendular (Codman's) shoulder exercises, Buerger–Allen exercises for peripheral vascular disease, Frenkel's exercises for ataxia, Williams' flexion and McKenzie extension regimens for the low back, Kegel/pelvic floor exercises, Frenkel-like oculomotor and Cawthorne–Cooksey exercises for vestibular rehabilitation.

Strength, power and endurance training

• Strength = maximum force in one effort; power = work per unit time; endurance = ability to sustain repeated contraction. Low load + high repetition builds endurance; high load + low repetition builds strength.
• 1RM / 10RM: the heaviest load liftable once / ten times through full range — the basis of dosage.
• DeLorme's progressive resistive exercise (PRE): 3 sets of 10 reps at 50%, 75% and 100% of 10RM; 10RM retested weekly. Warms up before the heaviest set.
• Oxford (regressive) technique: 100%, 75%, 50% of 10RM — accommodates fatigue; preferred in the early post-injury phase and in cardiac/elderly patients.
• MacQueen's regimen (hypertrophy: 4 sets of 10 at 10RM) and Zinovieff's (Oxford) are the other classically examined schemes.
• Typical prescription: strength 2–3 sessions/week, 2–4 sets of 8–12 reps at 60–80% 1RM; endurance 2–3 sets of 15–25 reps at 40–60%; isometric holds 6 s × 10 ("brief repetitive isometric exercise"), rest 1–3 min between sets, 48 h between sessions for the same group.
• Open vs closed kinetic chain: closed-chain (squat, leg press, step-up) gives co-contraction, lower patellofemoral/ACL graft shear and more functional carry-over; open-chain (knee extension on a boot) isolates a muscle and allows precise measurement.
• Adjuncts: suspension therapy (axial, vertical and pendular fixation for assisted or free movement in a gravity-eliminated plane), pulley circuits, weight-and-pulley, sandbags, weight boots, elastic bands (colour-graded resistance), medicine balls, Swiss ball, hydrotherapy (buoyancy assists, supports or resists; water temperature usually 34–37 °C).
• Limitations: DOMS, over-training, soft-tissue overload, hypertension or cardiac risk with heavy isometrics and the Valsalva manoeuvre, substitution by stronger synergists, and inability to progress safely in unstable fractures, acute inflammation, severe osteoporosis or unhealed wounds.

Flexibility, relaxation and neuromuscular re-education

• Stretching types: static (hold 15–60 s, 2–4 reps), dynamic/ballistic (bouncing — higher injury risk, limited use in sport warm-up), PNF stretching (hold-relax, contract-relax, agonist contraction) using autogenic inhibition via the Golgi tendon organ and reciprocal inhibition.
• Tissue behaviour: elasticity, viscoelasticity, creep (deformation under sustained load), stress-relaxation and plastic deformation — the reason low-load, long-duration stretch with heat is more lasting than a brief forceful pull.
• Contracture types: myostatic (reversible), arthrogenic, fibrotic/irreversible, pseudomyostatic (spasticity-driven) — management differs.
• PNF (Kabat–Knott–Voss): diagonal/spiral patterns (D1 and D2 for upper and lower limb), techniques — rhythmic initiation, repeated contractions, slow reversal, stabilising reversals, rhythmic stabilisation, hold-relax, contract-relax; principles — manual contact, stretch, traction/approximation, verbal command, irradiation.
• Other neuro approaches examined alongside: Bobath/NDT (inhibit abnormal tone, facilitate normal movement), Brunnstrom (use synergy), Rood (sensory facilitation), motor relearning programme, constraint-induced movement therapy, task-specific and repetitive practice (the evidence base for stroke rehabilitation).
• Coordination and balance: Frenkel's exercises — slow, precise, repeated, visually guided movements in lying → sitting → standing → walking, for sensory ataxia; balance progression — static to dynamic, wide to narrow base, eyes open to closed, firm to compliant surface (wobble board, balance pad), dual-task training; vestibular habituation and gaze stabilisation.
• Relaxation: Jacobson's progressive muscular relaxation (contract–relax of muscle groups in sequence), Mitchell's physiological relaxation (reciprocal relaxation by moving to the opposite position), breathing control, and general local and total relaxation positions.
• Breathing and thoracic exercises (overlapping cardiopulmonary PT): diaphragmatic breathing, segmental/localised expansion, pursed-lip breathing, incentive spirometry, thoracic mobility exercises, active cycle of breathing technique.

Gait re-education, functional and aerobic training

• Gait cycle: stance (~60%) — initial contact, loading response, mid-stance, terminal stance, pre-swing; swing (~40%) — initial, mid, terminal. Normal adult cadence ~100–120 steps/min, step length ~70 cm, walking speed ~1.2–1.4 m/s.
• Crutch/walker fitting: axillary crutch length ≈ patient's height − 41 cm, or 77% of height; axillary pad 5 cm (2–3 fingerbreadths) below the axilla; handpiece set so the elbow is flexed 20–30° (hand at the ulnar styloid/greater trochanter level). Elbow crutch and walker height = ulnar styloid/greater trochanter with 20–30° elbow flexion.
• Crutch gaits: four-point (max stability, needs both legs weight-bearing), two-point (faster), three-point (one limb non- or partial weight-bearing), swing-to and swing-through (paraplegia, needs strong shoulder depressors/triceps and latissimus dorsi), plus stair technique — "up with the good, down with the bad".
• Weight-bearing status: NWB, toe-touch/TTWB, partial (PWB, often 25–50% body weight, taught on weighing scales), weight-bearing as tolerated, full. Must match the surgeon's order.
• Functional and transfer training: bed mobility, rolling, sit-to-stand, pivot and sliding-board transfers, wheelchair propulsion, ADL retraining, ergonomics and back-care education.
• Aerobic prescription — FITT: Frequency 3–5 days/week; Intensity 40–80% heart-rate reserve, or RPE 11–14 on Borg 6–20; Time 20–60 min continuous or in 10-min bouts; Type walking, cycle ergometer, treadmill, aquatic. Public-health target ≈150 min/week moderate or 75 min vigorous, plus 2 days of resistance work. Always warm-up 5–10 min and cool-down 5–10 min.
• Monitoring and stopping rules: HR, BP, SpO₂, RPE, dyspnoea scale; stop for chest pain, giddiness, SpO₂ < 88–90%, SBP fall > 10 mmHg, SBP > 220 or DBP > 110 mmHg, new arrhythmia or severe fatigue. (Thresholds follow current ACSM/AACVPR guidance, which is revised periodically.)
• Indian practice and regulation: physiotherapy is a listed profession under the National Commission for Allied and Healthcare Professions Act, 2021, with a National Commission and State Allied and Healthcare Councils taking over registration — rollout is still in progress and some states also have their own councils, so confirm the current registration route in your state. BPT is a 4½-year degree (4 years + 6-month compulsory rotatory internship) under state health universities/UGC; the Indian Association of Physiotherapists (IAP) is the professional body. Rehabilitation entitlements flow from the Rights of Persons with Disabilities Act, 2016; physiotherapy sessions are packaged under Ayushman Bharat PM-JAY and CGHS at notified rates that are revised from time to time. Private out-patient sessions in metros typically run ₹300–₹800 and home visits ₹600–₹1,200 (indicative, 2026).

Key points

• Exercise therapy — graded movement used as treatment, to restore ROM, strength, endurance, balance, coordination and function.
• Overload and specificity - gains need a stimulus above habitual demand, and adapt to exactly the demand imposed (SAID).
• Reversibility - measurable strength loss begins within 2–3 weeks of stopping; detraining is faster than training.
• Oxford MMT scale - 0 to 5; grade 2 is full range with gravity eliminated, grade 3 full range against gravity.
• Goniometry - fulcrum on joint axis, stationary arm proximal, movable arm distal; record start and end angle, not just the range.
• Passive movement maintains range and tissue length; it does not build strength or prevent disuse atrophy.
• Isometric exercise - safe in immobilisation and acute pain, but strength gain is angle-specific and it raises BP via Valsalva.
• Eccentric contraction - greatest tension, most DOMS; the basis of tendinopathy loading programmes.
• Isokinetic - constant angular velocity with accommodating resistance; gives objective peak torque and H:Q ratio (~60% at 60°/s).
• DeLorme - 50/75/100% of 10RM (progressive); Oxford - 100/75/50% (regressive, fatigue-friendly).
• Closed kinetic chain - co-contraction, lower graft/patellofemoral shear, better functional transfer than open chain.
• Stretching - low-load long-duration with heat exploits creep; PNF hold-relax uses autogenic inhibition.
• Frenkel's exercises - slow, precise, visually monitored repetition for sensory ataxia, not for strength.
• Suspension therapy - axial fixation for free movement, vertical for assistance, pendular for relaxed oscillation.
• Hydrotherapy - buoyancy assists, supports or resists depending on movement direction; water usually 34–37 °C.
• Axillary crutch - height − 41 cm (≈77% of height), pad 5 cm below axilla, elbow flexed 20–30°.
• FITT - frequency, intensity, time, type; 150 min/week moderate aerobic plus 2 resistance days for general health.
• Borg RPE 6–20 - 11–14 corresponds to moderate intensity; useful when heart rate is unreliable (beta blockers, pacemaker, AF).

Formulas and examples

Example 1 — DeLorme vs Oxford dosage. A post-ACL-reconstruction patient's quadriceps 10RM (open-chain knee extension) is 12 kg.

• DeLorme: set 1 = 0.50 × 12 = 6 kg × 10; set 2 = 0.75 × 12 = 9 kg × 10; set 3 = 12 kg × 10. Total load lifted = 10 × (6 + 9 + 12) = 270 kg-reps.
• Oxford for the same patient on a fatiguing day: 12 kg → 9 kg → 6 kg (same total, heaviest set while fresh).
• Next week 10RM retests at 14 kg → sets become 7, 10.5 and 14 kg.

Example 2 — estimating 1RM and setting a training load. A patient performs leg press with 30 kg for 8 clean repetitions to failure.

• Denominator = 1.0278 − (0.0278 × 8) = 1.0278 − 0.2224 = 0.8054.
• 1RM = 30 / 0.8054 = 37.25 kg.
• Strength dose at 70% 1RM = 0.70 × 37.25 = 26.1 kg, so prescribe 3 × 10 at 26 kg; endurance dose at 50% = 18.6 kg for 3 × 20.

Example 3 — aerobic prescription by Karvonen. A 55-year-old man, 6 weeks after an uncomplicated myocardial infarction, resting HR 72 bpm, not on a beta blocker.

• HRmax ≈ 220 − 55 = 165 bpm; HRR = 165 − 72 = 93 bpm.
• 50% intensity: 72 + (0.50 × 93) = 72 + 46.5 = 118 bpm; 70%: 72 + 65.1 = 137 bpm.
• Prescription: treadmill walking, 5 days/week, 30 min, HR window 118–137 bpm, RPE 11–13, with 5-min warm-up and cool-down.
• Caution: if he were on a beta blocker or pacemaker, 220 − age is invalid — use a symptom-limited exercise-test HR or Borg RPE.

Example 4 — torque on the knee from a weight boot. Patient in sitting, shin + foot weigh 4 kg with centre of gravity 22 cm from the knee axis; a 3 kg weight boot sits 35 cm from the axis.

• Limb torque = 4 × 9.81 × 0.22 = 8.63 N·m; boot torque = 3 × 9.81 × 0.35 = 10.30 N·m.
• Total resisting torque with the leg horizontal (θ = 0°) = 18.93 N·m.
• At 30° short of full extension (θ = 30° below horizontal): 18.93 × cos 30° = 18.93 × 0.866 = 16.40 N·m — torque falls as the limb moves away from horizontal, which is why peak demand is at terminal extension.
• To halve the boot's contribution without changing the weight, move it to 17.5 cm: 3 × 9.81 × 0.175 = 5.15 N·m.

Example 5 — energy cost and 6MWT interpretation. A 60 kg woman walks on a treadmill at an intensity of 4 METs for 30 minutes.

• VO₂ = 4 × 3.5 = 14 ml/kg/min = 14 × 60 = 840 ml/min = 0.84 L/min.
• Energy = 4 × 3.5 × 60 / 200 = 4.2 kcal/min → 4.2 × 30 = 126 kcal per session; about 5 such sessions ≈ 630 kcal.
• Separately, a 65-year-old man, 165 cm, 70 kg, walks 420 m in a 6MWT. Predicted = (7.57 × 165) − (5.02 × 65) − (1.76 × 70) − 309 = 1249.05 − 326.30 − 123.20 − 309 = 490.6 m → 420/490.6 = 85.6% of predicted, a mild reduction. A 30 m gain after training would be clinically meaningful.

Where it is used

• Hospital physiotherapy departments (AIIMS, PGIMER, CMC Vellore, Apollo, Fortis, Max, Manipal, KEM): post-operative orthopaedic protocols — THR/TKR, ACL, fracture and spine rehabilitation; ICU early mobilisation.
• Neuro-rehabilitation units and NGOs/CRCs under the RPwD Act: stroke, spinal cord injury, cerebral palsy, Parkinson's disease — PNF, NDT, task-specific training, gait and balance re-education.
• Cardiopulmonary rehabilitation (Phase I–IV programmes, post-COVID and post-CABG clinics): graded aerobic prescription, breathing exercises, 6MWT and ergometry-based progression.
• Sports physiotherapy — IPL and ISL teams, SAI and NCOE centres, academies: strength and conditioning, eccentric loading, return-to-play testing with isokinetic and hop tests.
• Home healthcare and tele-rehabilitation (Portea, HealthCare atHOME, Practo-listed clinics): home exercise programmes, geriatric fall-prevention, antenatal and postnatal exercise.
• Industry and corporate wellness, and clinic ownership: ergonomic assessment, back-school programmes, pre-employment fitness, and self-run practices (equipment: parallel bars, suspension frame, shoulder wheel, static cycle, pulleys, exercise mats).

Interview questions

• Q: What is the difference between active-assisted and resisted exercise, and when do you choose each? A: Assisted exercise supplies the force the patient cannot generate and suits MMT grades 1–2; resisted exercise adds load beyond gravity for grades 4–5 to build strength.
• Q: A patient has MMT grade 2 quadriceps. What exercise do you give? A: Gravity-eliminated active-assisted knee extension — side lying or sitting with the limb in sling suspension, plus static quadriceps and inner-range holds; no weights yet.
• Q: Why is passive movement not a substitute for active exercise? A: It maintains joint range, tissue length and circulation but produces no voluntary muscle contraction, so it neither increases strength nor prevents disuse atrophy.
• Q: Compare DeLorme and Oxford techniques. A: Both use 3 sets of 10 at 50/75/100% of 10RM; DeLorme ascends (acts as a warm-up), Oxford descends (accommodates fatigue), so Oxford suits early rehabilitation and frail or cardiac patients.
• Q: Why are isometric exercises preferred immediately after knee surgery? A: They generate muscle tension and limit atrophy without joint movement or shear across healing tissue — but they must be taught with normal breathing to avoid the Valsalva BP rise.
• Q: What is the physiological basis of PNF hold-relax stretching? A: An isometric contraction of the shortened muscle stimulates its Golgi tendon organs, producing autogenic inhibition and a brief drop in resistance that allows more range on release.
• Q: How do you measure an axillary crutch? A: Roughly height minus 41 cm (or 77% of height), with the axillary pad about 5 cm below the axilla and the handgrip set at the ulnar styloid so the elbow is flexed 20–30°.
• Q: Which crutch gait for a non-weight-bearing tibial fracture, and what muscles must be strong? A: A three-point gait; shoulder depressors, triceps, latissimus dorsi and grip must be trained, along with the sound limb's quadriceps and hip abductors.
• Q: Open or closed kinetic chain after ACL reconstruction, and why? A: Favour closed-chain (squats, step-ups, leg press in a safe arc) early, because co-contraction reduces anterior tibial shear on the graft; add open-chain knee extension later within protected range.
• Q: Your patient is on a beta blocker. How do you set aerobic intensity? A: 220 − age is unreliable, so prescribe by Borg RPE 11–14, by the talk test, or from a symptom-limited exercise test performed on the same medication.
• Q: Give three absolute contraindications to vigorous exercise therapy. A: Unstable angina or decompensated heart failure, acute DVT before anticoagulation is established, and an unstable or unhealed fracture; also uncontrolled arrhythmia, acute systemic infection with fever, and resting SBP above about 200 mmHg.
• Q: How do you know your exercise programme is working? A: Re-measure the same outcomes — goniometric ROM, MMT or 1RM, girth, 6MWT distance (MCID ≈ 30 m), Berg Balance or TUG, pain NPRS and a functional scale — at fixed intervals and compare with baseline.

Common mistakes

• Writing ROM as a single number ("knee 130°") without the starting angle, so a 10° extension lag is hidden.
• Testing MMT with the wrong starting position or allowing substitution — e.g. trunk side flexion during shoulder abduction, or hip flexor substitution for quadriceps.
• Giving resisted exercise to a grade 2 muscle, or passive movement to a patient who can move actively.
• Using 220 − age blindly on patients taking beta blockers, on pacemakers or in atrial fibrillation.
• Forgetting the weight of the limb itself when calculating resistance torque, and ignoring the cos θ fall-off through range.
• Letting the patient hold the breath (Valsalva) during isometric or heavy resisted work, risking a sharp BP rise.
• Progressing load, range and repetitions all in the same session, so a flare-up cannot be attributed to any one change.
• Quoting a protocol (DeLorme, Williams, Frenkel) by name in a viva without being able to state its dosage, indication and progression.

Related topics

Electrotherapy · Orthotics and prosthetics · Musculoskeletal and orthopaedic physiotherapy · Neurological physiotherapy and rehabilitation · Cardiopulmonary physiotherapy and exercise testing · Biomechanics and kinesiology