ACVSMR cheat sheet

The sarcomere is the functional unit of muscle; its length-tension relationship dictates that active force is maximal at optimal overlap of actin and myosin filaments and declines when over- or under-shortened.

Muscle fiber types: Type I (slow-twitch, oxidative, fatigue-resistant) vs Type II (fast-twitch, glycolytic, high force, fatigable); training induces fiber-type shifts and enzymatic adaptations.

Tendon viscoelasticity: stress-strain curve has toe region (crimp straightening), linear region (elastic), and yield/failure; stiffness increases with training, and creep is time-dependent deformation under constant load.

Bone remodeling follows Wolff's law: load magnitude and direction drive osteoblast/osteoclast activity; cyclic loading below threshold is osteogenic, whereas immobilization causes disuse osteopenia.

Joint biomechanics: concave-convex rule-convex surface moving on concave (or vice versa) determines roll and glide direction for safe mobilization.

Equine hoof-pastern axis alignment and heel-to-toe ratio affect load distribution; long toe/low heel increases strain on the deep digital flexor tendon and navicular apparatus.

Canine stifle: cranial cruciate ligament resists cranial tibial translation and internal rotation; its rupture alters joint kinematics and predisposes to meniscal injury and osteoarthritis.

Gait analysis fundamentals: stance vs swing phase, duty factor, stride length, and ground reaction forces; symmetry indices quantify lameness by comparing limb impulse.

Muscle physiology: eccentric contractions generate higher force with lower metabolic cost but greater delayed-onset muscle soreness and sarcomere strain injury risk.

Orthopedic exam sequence: observation (conformation, posture, gait), palpation (effusion, crepitus, muscle atrophy), range-of-motion testing, and provocative tests (e.g., cranial drawer, Ortolani, flexion tests).

Lameness grading in horses uses the AAEP 0–5 scale; canine lameness is often graded 0–4 based on weight-bearing and gait alteration.

Radiography remains first-line for bone and joint disease; orthogonal views are mandatory, and stress views can reveal ligamentous instability.

Ultrasonography is preferred for soft tissue (tendon, ligament, muscle) evaluation; anisotropy artifact can mimic lesions if the probe angle is not optimized.

MRI provides superior soft-tissue contrast for cruciate ligament, meniscal, and spinal cord lesions; contraindications include metallic implants and patient size limitations.

CT is ideal for complex fractures, bone tumors, and dental disease; contrast CT aids vascular and neoplastic characterization.

Nuclear scintigraphy (bone scan) is highly sensitive for occult osseous injury in horses (e.g., stress fractures) but has low specificity.

Objective gait analysis systems (force plates, pressure mats, inertial sensors) improve lameness detection sensitivity compared with subjective visual assessment.

Progressive overload principle: training stimulus must exceed current capacity, with gradual increases in intensity, duration, or frequency to drive adaptation without injury.

Specificity of training: adaptations are specific to the muscles, joint angles, and energy systems trained; rehabilitation exercises should mimic functional demands.

Core strengthening (transverse abdominis, multifidus, pelvic floor) improves spinal stability and is a foundation for return-to-function in canine and equine athletes.

Aquatic therapy: buoyancy reduces weight-bearing load (up to ~85% at chest depth in dogs), while water viscosity provides resistance and supports controlled movement.

Plyometric and proprioceptive training (cavaletti poles, wobble boards, balance pads) enhance neuromuscular control and reduce reinjury risk.

Eccentric exercise protocols are used for tendinopathy (e.g., Achilles, superficial digital flexor tendon) to stimulate collagen remodeling and increase tendon stiffness.

Conditioning programs should follow periodization: base building (aerobic), strength/power phases, and tapering before competition to optimize performance and recovery.

Monitoring training load via heart rate, lactate, and GPS-derived speed/distance helps prevent overtraining syndrome in equine and canine athletes.

Therapeutic ultrasound: continuous mode produces deep heating (via cavitation and acoustic streaming) at 1–3 MHz; pulsed mode is non-thermal and used for soft-tissue healing; avoid over growth plates, neoplasia, or pregnant uterus.

Electrical stimulation: TENS (high frequency, sensory-level) for pain modulation via gate control; NMES (low frequency, motor-level) for muscle re-education and atrophy prevention.

Laser therapy (photobiomodulation): wavelengths 600–1100 nm penetrate tissue; doses are calculated as energy density (J/cm²) and vary by tissue depth and condition.

Cryotherapy reduces edema and pain via vasoconstriction and decreased nerve conduction; apply for 15–20 minutes with a barrier to prevent cold burns.

Thermotherapy increases tissue extensibility and blood flow; contraindicated in acute inflammation, hemorrhage, or areas with impaired sensation.

Manual therapy techniques include joint mobilization (grades I–V per Maitland), soft-tissue mobilization, myofascial release, and stretching; grade V (manipulation) involves high-velocity thrust.

Extracorporeal shockwave therapy (ESWT) stimulates neovascularization and tissue regeneration; common equine indications include suspensory desmitis and navicular syndrome.

Acupuncture and dry needling modulate pain via endogenous opioid release and local blood flow; evidence supports use as adjunctive analgesia in canine and equine practice.

Pre-participation screening identifies conformational faults, muscle imbalances, and subclinical lameness that predispose to injury; findings guide individualized conditioning.

Return-to-sport criteria: pain-free full range of motion, symmetric strength and proprioception, sport-specific functional testing, and gradual load reintroduction.

Functional testing examples: timed walk/trot, jump landing mechanics, single-leg stance, and isokinetic strength testing to compare limb symmetry (goal >90%).

Load management: acute:chronic workload ratio >1.5 is associated with increased injury risk in human and animal athletes; gradual progression is protective.

Warm-up increases muscle temperature, tendon compliance, and nerve conduction velocity, reducing injury risk; cool-down aids metabolic waste clearance.

Performance assessment in horses includes heart rate recovery, lactate threshold, and stride characteristics; in dogs, gait symmetry and endurance tests are used.

Reinjury prevention requires addressing underlying causes (e.g., saddle fit, footing, training surface, shoeing) and periodic reassessment.

Canine athletes: common injuries include cranial cruciate ligament rupture, iliopsoas strain, and carpal/tarsal sprains; agility and flyball dogs are at risk for shoulder and digit injuries.

Equine disciplines: racehorses-stress fractures, superficial digital flexor tendinitis; dressage-hindlimb suspensory and hock issues; show jumpers-navicular and suspensory injuries; eventers-traumatic injuries.

Feline sports medicine is emerging; common issues include patellar luxation, hip dysplasia, and osteoarthritis; cats require low-stress handling and species-specific exercise prescriptions.

Equine hoof care and shoeing influence biomechanics; corrective shoeing can alter breakover and load distribution for conditions like laminitis or navicular syndrome.

Canine conditioning should include strength, balance, and endurance; avoid excessive repetitive jumping in growing dogs to protect growth plates.

Equine fitness: interval training improves aerobic capacity; monitoring recovery heart rate and lactate guides training intensity.

Species differences in pain expression: cats mask pain; dogs may show subtle gait changes; horses exhibit behavioral and postural indicators-use validated pain scales.

Scope of practice: rehabilitation providers must work within their licensure and collaborate with veterinarians for diagnosis and treatment planning.

Informed consent: owners must understand risks, benefits, and alternatives before initiating rehabilitation or performance interventions.

Record keeping: document assessments, treatments, progress, and client communication; records are legal documents and support continuity of care.

Evidence-based practice: integrate best available research, clinical expertise, and patient/owner values; avoid unproven modalities without owner disclosure.

Welfare and ethics: prioritize animal welfare, avoid painful or unnecessary procedures, and recognize signs of distress; use humane handling techniques.

Team approach: veterinarians, veterinary technicians, physical therapists, and trainers collaborate; clear communication prevents conflicting interventions.

Business and case management: cost-benefit analysis of modalities, client education for home exercise compliance, and scheduling follow-ups to monitor outcomes.