TSAC-F key terms

The speed at which a muscle or muscle group can generate force, reflected in the slope of the force-time curve. High values support explosive tasks such as sprinting, striking, and rapid direction changes.

A rapid eccentric lengthening of a muscle followed immediately by a concentric shortening. Elastic energy stored during the lengthening phase is released, producing more force than a concentric action alone.

The nervous system's activation of additional motor units to increase force output, generally progressing from smaller, slower units to larger, faster ones. Recruitment and firing rate together determine how much force is produced.

The highest rate at which the body can take up and use oxygen during intense exercise, expressed in milliliters per kilogram per minute. It reflects aerobic power and supports sustained occupational work.

The exercise intensity at which blood lactate accumulates faster than it can be cleared. Training near this point improves the fastest pace an athlete can hold during long tactical efforts.

The immediate energy system that uses stored ATP and creatine phosphate to fuel very brief, maximal efforts of roughly ten seconds or less, such as a forced entry or a short sprint.

A prolonged decline in performance accompanied by fatigue, mood disturbance, and poor sleep, caused by training stress that consistently exceeds recovery capacity. It can take weeks or months to resolve.

The rebound above baseline fitness that follows an adequate recovery period after a training stimulus. Programming relies on it to time the next overload bout.

The partial or complete loss of training adaptations when the training stimulus is removed or sharply reduced. Strength, power, and aerobic capacity decline at different rates during layoffs.

A subjective numeric scale describing how hard an effort feels. It is used to prescribe and monitor intensity when heart rate, velocity, or load data are unavailable.

A structured review of the physical demands of the job or sport, the athlete's current capacities, and the equipment and time available. It drives every later programming decision.

Gradually increasing training stress through load, volume, density, or complexity so that the body keeps adapting instead of plateauing. Increases should be small enough to preserve technique.

The planned manipulation of training variables across time blocks to manage fatigue, reduce injury risk, and peak performance for a specific event or assessment.

A training block lasting several weeks to a few months that emphasizes a specific goal, such as strength, hypertrophy, or work capacity, within a larger annual plan.

The shortest planned training block, usually about one week, describing how sessions, loads, and recovery days are arranged day to day.

A measure of resistance training work calculated by multiplying sets by repetitions by the load lifted. Coaches use it to track and progress weekly training stress.

The heaviest load an athlete can lift for a given number of correct repetitions; a one-repetition maximum is the standard reference for setting intensity as a percentage of maximum.

Programming resistance and aerobic training together. Careful sequencing and spacing of sessions limit the interference effect so that strength and endurance adaptations can both develop.

Adjusting the day's training load or volume based on readiness indicators such as perceived exertion, movement velocity, or heart rate variability, rather than following a fixed prescription.

A planned reduction in training volume, and sometimes intensity, before a key event or fitness test. The goal is to shed fatigue while keeping the adaptations already gained.

The adjustable components of a training session: exercise choice and order, intensity, volume, rest periods, tempo, and frequency. Together they determine the stress applied and the resulting adaptation.

A breath held against a closed glottis during a heavy lift, which raises intra-abdominal pressure and stiffens the trunk. It also sharply raises blood pressure, so it is used selectively.

Co-contracting the trunk muscles while breathing into the diaphragm to create pressure around the spine. This stiffness protects the back while force is transferred through the body.

A movement in which the hips travel backward while the spine stays neutral, loading the glutes and hamstrings. It underpins deadlifts, kettlebell swings, and many lifting tasks performed on duty.

Keeping the natural cervical, thoracic, and lumbar curves without excessive rounding or arching. Maintaining it under load distributes force safely through the discs and joints.

A progression of controlled, movement-specific drills that raise tissue temperature, take joints through their ranges, and prime the nervous system before training or a shift.

Exercises that use quick stretch-shortening actions, such as jumps, hops, and bounds, to build explosive power. They require adequate strength, landing control, and a gradual progression.

How the lower body aligns and absorbs force when touching down from a jump. Good mechanics use hip and knee flexion and avoid the knees collapsing inward.

A systematic look at fundamental patterns such as squatting, lunging, and reaching to find restrictions or left-right asymmetries that may raise injury risk as training loads rise.

A service member, law enforcement officer, or firefighter whose job demands physically strenuous, high-stakes tasks. Training is organized around occupational performance rather than sport competition.

The capacity to perform the specific tasks a job requires, such as climbing ladders, dragging a casualty, or carrying equipment, measured against job-related standards.

Moving while wearing a pack or protective equipment. Added mass raises metabolic cost and musculoskeletal strain, making it a defining demand of tactical work.

A loaded foot march over distance with a backpack. It is used both as training and as an assessment of aerobic endurance, load tolerance, and lower-body durability.

The variation in time between successive heartbeats, reflecting autonomic nervous system balance. Lower variability or a sharp drop from baseline can signal incomplete recovery.

Habits that support consistent, restorative sleep, such as a regular schedule, a dark cool room, and limiting caffeine and screens before bed. Poor sleep impairs recovery and decision-making.

The dietary energy left for normal body functions after exercise energy expenditure is subtracted. Persistently low availability harms recovery, hormones, bone health, and performance.

Working rotating, night, or extended schedules that disrupt circadian rhythm and sleep. It raises fatigue, injury risk, and recovery demands, so training and nutrition need adjusting.

A validated, job-related test battery defining the minimum physical capacity needed to safely perform essential duties. It supports hiring, fitness-for-duty, and return-to-work decisions.

The capacity to adapt to stress, adversity, and demanding operational conditions while maintaining performance and well-being. It is built through sleep, recovery, coping skills, and graded exposure to stress.