Dr. Frederick Hatfield, also known as “Dr. Squat,” was a pioneering strength coach, powerlifter, and sports scientist. His work in strength training methodology laid the foundation for many of today’s training principles. Below is a lexicon of key terms used by Hatfield throughout his career.
A
- Absolute Strength – The total amount of force an individual can generate regardless of time or speed.
- Acceleration Training – A focus on moving weight with increasing speed throughout the lift.
- Adaptive Response – The body’s ability to adapt to progressively increased training demands.
B
- Ballistic Training – A method of explosive training that involves moving a load as quickly as possible.
- Biomechanics – The study of movement mechanics as they relate to strength training and sports performance.
- Bodybuilding Training – Training focused on muscular hypertrophy through high-volume, moderate-intensity lifting.
C
- Compensatory Acceleration Training (CAT) – A method of lifting where force is applied maximally throughout the entire range of motion to accelerate the bar.
- Concentric Contraction – The shortening phase of a muscle contraction during a lift.
- Cross-Education Effect – Strength improvements in an untrained limb due to training the opposite limb.
D
- Dynamic Effort (DE) Training – A speed-strength method used to improve explosive power.
- Double Progression – A method of progressive overload where both weight and reps increase over time.
- Density Training – A training approach that increases the amount of work performed in a given time.
E
- Eccentric Training – A focus on the negative portion of a lift to build strength and control.
- Energy Systems – The metabolic pathways used to fuel exercise, including ATP-PC, glycolytic, and oxidative systems.
- Explosive Strength – The ability to generate force rapidly, crucial for power sports.
F
- Fast-Twitch Muscle Fibers – Muscle fibers responsible for explosive movements and maximal strength.
- Force-Time Curve – A representation of how force production changes over time in a lift.
- Fatigue Management – The process of balancing training stress with recovery.
G
- General Adaptation Syndrome (GAS) – A model describing the body’s response to stress, including alarm, adaptation, and exhaustion phases.
- General Physical Preparedness (GPP) – Foundational fitness work used to enhance recovery and overall work capacity.
- Golgi Tendon Organ (GTO) – A sensory receptor that limits force output to protect against injury.
H
- Hypertrophy-Specific Training (HST) – A systematic approach to muscle growth based on principles of progressive overload and muscle fiber recruitment.
- Hormonal Response to Training – The effect of strength training on hormones like testosterone, growth hormone, and cortisol.
- High-Intensity Training (HIT) – A low-volume, high-effort approach to training.
I
- Intermuscular Coordination – The efficiency of muscle groups working together in complex movements.
- Intramuscular Coordination – The ability of muscle fibers within a muscle to fire synchronously for greater force production.
J
- Jump Squats – An explosive squat variation used to build power and speed.
- Joint Stability – The ability of joints to maintain position under load.
K
- Kinetic Chain – The sequence of joint and muscle activation in movement.
- Kinetic Energy – The energy generated by movement and force application.
L
- Linear Periodization – A training method that progressively increases intensity while decreasing volume over time.
- Load-Intensity Relationship – The correlation between weight lifted and muscle activation.
M
- Maximal Effort (ME) Method – Lifting at 90-100% of one’s 1RM to develop maximal strength.
- Motor Unit Recruitment – The activation of motor neurons in response to training.
N
- Neuromuscular Efficiency – The nervous system’s ability to recruit muscle fibers effectively.
- Negative Work – Eccentric-focused training to enhance strength and muscle growth.
O
- Overcompensation Principle – The idea that muscles adapt by becoming stronger after being exposed to stress.
- Overload Principle – A fundamental training concept stating that progressive increases in resistance are necessary for growth.
P
- Powerlifting – A strength sport consisting of the squat, bench press, and deadlift.
- Progressive Overload – Gradually increasing training intensity to force adaptation.
- Pre-Exhaustion Training – A method where an isolation exercise is performed before a compound movement to pre-fatigue the target muscle.
Q
- Quadriceps Dominance – A movement pattern where the quads take over rather than engaging the posterior chain effectively.
R
- Rate of Force Development (RFD) – The speed at which force is generated.
- Reactive Strength – The ability to rapidly transition from eccentric to concentric movements.
- Recovery Curve – The time required for full recovery between training sessions.
S
- Specific Adaptation to Imposed Demands (SAID) – The principle that the body adapts to the specific stresses placed upon it.
- Speed Strength – The ability to generate force rapidly with minimal resistance.
- Supercompensation – The process of the body over-recovering after training, leading to increased performance.
T
- Time Under Tension (TUT) – The duration a muscle is under strain during a set.
- Tendon Stiffness – The ability of tendons to store and release energy efficiently.
- Triple Extension – The simultaneous extension of the hips, knees, and ankles in explosive movements.
U
- Undulating Periodization – A non-linear model where intensity and volume fluctuate frequently to avoid adaptation.
V
- Velocity-Based Training (VBT) – A training approach where load is adjusted based on movement speed.
- Volume Load – The total amount of weight lifted in a session (sets × reps × weight).
W
- Wave Loading – A method of fluctuating intensity within a session or cycle to maximize strength gains.
- Work Capacity – The ability to sustain high levels of training without excessive fatigue.
X-Y-Z
- X-Factor in Training – The unique, individual variables that influence training responses.
- Yielding Isometrics – Holding a load at a fixed position to build strength and endurance.
This lexicon highlights the essential terminology used by Dr. Frederick Hatfield, reflecting his deep understanding of biomechanics, physiology, and strength training science. His principles remain foundational in modern strength and conditioning.