ACVSMR key terms

The smallest contractile unit of a muscle fiber, bounded by two Z-lines and containing overlapping actin and myosin filaments whose sliding produces shortening and force generation.

The model explaining muscle contraction whereby myosin heads bind actin, pivot, and pull thin filaments toward the sarcomere center, shortening the fiber without changing filament length.

The repeated sequence of myosin head attachment to actin, power stroke, release, and re-cocking fueled by ATP, which generates tension during muscle contraction.

The arrangement of muscle fibers relative to the line of pull, such as parallel, pennate, or fusiform, which determines force output, excursion, and contraction velocity.

The angle at which muscle fibers insert into the tendon aponeurosis; larger angles pack more fibers for force but reduce the distance the muscle shortens.

The principle that a muscle generates maximal active tension at an optimal sarcomere overlap and less tension when overly shortened or stretched.

The inverse relationship in which a muscle produces greater force during slow or eccentric contractions and less force as shortening velocity increases.

A contraction in which the muscle lengthens while producing tension, absorbing energy and causing high mechanical stress on muscle-tendon units.

Muscle discomfort and stiffness peaking one to three days after unaccustomed or eccentric exercise, reflecting microdamage and inflammation rather than acute injury.

Abbreviation for delayed-onset muscle soreness; clinicians assess it to gauge exercise load tolerance and to distinguish benign soreness from strain injury.

The complete sequence from initial contact of one limb to the next contact of the same limb, divided into stance and swing phases used to analyze locomotion.

The portion of the gait cycle during which a limb contacts and supports the body, absorbing and then propelling the animal forward.

The proportion of the gait cycle a limb spends in stance; it increases at faster gaits and determines whether a gait has suspension phases.

The point representing the average position of body mass, whose movement relative to the base of support determines postural stability and limb loading.

The area bounded by the contact points of the limbs with the ground within which the center of mass must remain for stable standing.

The branch of biomechanics describing motion without reference to forces, including joint angles, velocities, stride length, and temporal gait variables.

The study of forces that cause or result from motion, including ground reaction forces, joint moments, and muscle forces acting on the body.

The force exerted by the ground on a limb during contact, measured with force plates to quantify loading, symmetry, and limb offloading.

The vertical component of ground reaction force, expressed as a percentage of body weight, used to compare limb loading and detect asymmetry.

A structured clinical assessment combining observation, palpation, and provocation or gait evaluation to localize and grade a musculoskeletal source of altered movement.

A standardized ordinal score describing the severity of an abnormal gait, used to document baseline status and monitor response to treatment.

Local anesthetic blockade of specific nerves or joints to determine whether a region is the source of pain causing lameness.

Injection of local anesthetic around a peripheral nerve to desensitize its territory, used to localize the source of lameness in horses.

Real-time imaging using high-frequency sound waves to evaluate soft tissues such as tendons, ligaments, and muscle, including fiber pattern and lesion size.

An ultrasound mode that detects and displays blood flow, used to assess perfusion and neovascularization within injured tendons and other tissues.

A chronic degenerative condition of a tendon characterized by disorganized collagen, pain, and impaired function, often without acute inflammation.

A rehabilitation principle of gradually increasing mechanical stress on healing tissues to stimulate adaptation while avoiding overload and re-injury.

Structured, dosed physical activity prescribed to restore strength, mobility, and function, with intensity and duration tailored to tissue healing stage.

Planned, repetitive bodily movement prescribed to improve or maintain strength, flexibility, endurance, balance, and functional performance.

The sense of joint position and movement derived from mechanoreceptors in muscles, tendons, and joints, essential for balance and coordinated limb control.

The capacity of trunk and spinal musculature to control posture and stabilize the body during limb movement, supporting efficient locomotion.

Systematic training that improves cardiovascular fitness, muscular strength, and endurance in preparation for athletic work and to reduce injury risk.

A pre-exercise period of gradually increasing activity that raises tissue temperature and prepares neuromuscular and cardiovascular systems for performance.

A gradual reduction in exercise intensity following training that promotes recovery and returns cardiovascular and respiratory function toward resting levels.

Objective benchmarks such as pain-free loading, symmetrical strength, and normal gait that must be met before resuming full athletic activity.

Delivery of high-energy acoustic pulses to tissues to stimulate healing and reduce pain in chronic musculoskeletal conditions such as tendinopathy.

Application of high-frequency sound waves to deep tissues to produce thermal and nonthermal effects intended to promote healing and reduce pain.

Therapeutic application of cold to reduce tissue temperature, pain, and swelling, commonly used after acute injury or intense exercise.

Hands-on techniques such as joint mobilization, stretching, and soft-tissue manipulation used to improve mobility, reduce pain, and restore function.