Plyometric Training Adaptations

• Rate of adaptation, performance, and training complexity increase over time as the athlete moves from untrained to advanced

Background

• Muscle-tendon units create elastic energy during eccentric stretch
• Elastic energy is briefly stored, then used during the subsequent concentric contraction
• Faster eccentric contraction results in greater force production in concentric contraction
• Proprioceptors of muscles, tendons, ligaments and joints are stimulated
• Eccentric contraction stimulates the monosynaptic stretch reflex
• Muscle spindles sense muscle length and velocity of stretch; this is transmitted to the CNS
• The CNS sends efferent signals to the muscle to activate a shortening contraction

Adaptations in the Musculoskeletal System

• Increase in muscle fiber diameter (hypertrophy)
• Increase in muscle fiber length (sarcomerogenesis)
• Increase in the angle of muscle fibers inside the muscle (pennation angle)
• Increases in fiber diameter, fiber length, and pennation angle at different parts of a muscle (regional hypertrophy)
• Muscle fibers shift from type IIX to type IIA
• The amount of force transmitted laterally from the muscle fiber to surrounding collagen tissues increases
• Increase in the stiffness of surrounding collagen tissues
• Tendon stiffens

Adaptations in the Neurological System

• Activation of the prime mover muscles (agonists) increases
• Agonists are activated earlier and faster
• Increased activation of agonists happens at some joint angles, not others
• The activation of opposing muscles (antagonists) decreases
• Activation of synergists increases, allowing the body to be positioned more effectively for force production
• Improvements in coordination from increased motor skill
• The excitability of the neuromuscular receptors increases
• Improved reactivity of the neuromuscular system

Adaptations in the Vascular System

• The number of capillaries supplying blood inside the muscle increases
• Buffering capacity and rate of ion transport inside a muscle fiber changes
• Fatigue reduces
• Edema reduces

Terminology

• Essential terminology for developing power and plyometric training programs:
• Exercise selection
• Exercise order
• FITTVP
• Type of muscle contractions (concentric, eccentric)
• Range of motion
• Rate of force production
• Load
• Stability

Exercise Selection

• Manual resistance involves a partner providing resistance
• Mechanical resistance is provided by equipment
• Constant resistance is where the load remains the same
• Variable resistance varies throughout the range of motion (bands, machines)
• Accommodating resistance involves specialized machines that adjust resistance
• Isokinetic resistance controls the velocity of movement
• Body weight resistance uses the individual’s own weight as resistance

Exercise Order

• Fatigue accumulates throughout a training session
• Better adaptation from exercises occurs early in the session
• Greater hypertrophy in muscles worked in the session first
• Consider session goals like strength vs. power vs. motor control
• Common exercise order methods:
  • Upper body and lower body split
  • Muscle group split
  • Multi-joint before single joint
  • Power movements first
  • Large muscles groups before small
  • Alternate agonist/antagonist
  • Push-Pull

FITTVP - ACSM Power Training Recommendations

• Healthy Adults frequency is 2+ times per week
  • Intensity:
    • Upper Body: 30%-60% of 1-RM
    • Lower Body: 0%-60% of 1-RM
    • Low RPE and high RIR
  • Time:
    • 1-3 sets of 3-6 repetitions per exercise
    • More than two minutes of rest between sets
  • Type: Performed with the intent to move the resistance with maximal velocity
    • Relate to goal tasks
  • Volume: Insufficient evidence to make recommendations
  • Progression: Speed or Load
• Untrained or Older Adults frequency is 2+ times per week
  • Intensity:
    • Upper Body: 30%-60% of 1-RM
    • Lower Body: 0%-60% of 1-RM
    • Low RPE and high RIR
  • Time:
    • 1-3 sets of 6-10 repetitions per exercise
    • More than two minutes of rest between sets
  • Type: High velocity
    • Focus on the major muscle groups of the upper and lower body (i.e. quads, triceps, etc.)
    • Minimize fall risk
  • Volume: Insufficient evidence to make recommendations
  • Progression: Speed or Load

FITTVP - Morrison, et al

• Energy System Training Distribution
  • Explosive Efforts
    • Maximal intensity for up to 6 seconds with 3-5s work: 60-120s rest
  • High Intensity Efforts
    • Maximal intensity for 6 seconds to 1 minute with 30s work: 30s rest
  • Endurance Efforts
    • Maximal intensity for greater than 1 minute with 3min work: 3min rest

Type of Muscle Contraction

• Peak Velocity improves with shorter eccentric times under tension (