Lecture 6: Plyometric Training Flashcards
Mechanical Model
series elastic component (SEC)
-SEC
elastic energy is stored during an eccentric action, then released during an immediate concentric muscle action
- contributes to total force production by naturally returning muscles/tendons to their un-stretched configuration
- if concentric action does not occur immediately or the eccentric phase is too long the stored energy is lost as heat
PED
parallel elastic component
-epimysium, perimysium, endomysium, & sarcolemma exerts a passive force with unstimulated muscle stretch
Neurophysiological Model
Potentiation fig. 16.2
Potentiation
change in force velocity characteristics of the muscle’s contractile components due to the stretch reflex (muscle spindles)
-if concentric muscle action does not occur immediately after the pre-stretch the potential energy is lost
Muscle Spindles
proprioceptive organs that detect a quick stretch and respond by increasing muscular activity (involuntary protective response)
-creates a breaking effect, allowing for a powerful concentric action
Stretch Shortening Cycle (SSC)
- incorporates both the energy storage capabilities of the SEC and the stimulation of the stretch reflex to facilitate a max increase in muscle recruitment of a minimal amount of time
- Plyos use SSC that ultimately increase the power of subsequent movements in the shortest possible time
SSC phases
1) eccentric
2) amortization
3) concentric
Eccentric Phase
- stretch of agonist muscle
- elastic energy is stored in the SEC
- muscle spindles are stimulated
Amortization phase
- pause between phases
- type Ia afferent nerves synapse with alpha motor neurons
- alpha motor neurons transmit signals to agonist muscle group
Concentric Phase
- shortening of agonist muscle
- elastic energy is released from the SEC (mechanical)
- alpha motor neurons stimulate the agonist muscle group (neurophysiological)
SSC combines…
mechanical and neurophysiological mechanisms
- is the basis of plyos
- rapid eccentric muscle action stimulates the stretch reflex and storage of elastic energy which increase force produced during subsequent concentric action
Highest Jump
1) Approach Jump
2) Countermovement Jump
3) Static Squat Jump
Lower Body Plyos
Jumps in place standing jumps multiple hops and jumps bounds box drills depth jumps
Jumps in Place
- jump and land in same spot without rest
- emphasis on vertical
- amortization phase: between jumps
ex) squat jump, tuck jump, split-squat jump, pike jump
Standing Jumps
emphasis on horizontal vertical component
- max effort with recovery between reps
- ex) vertical jump, jump over barriers
Multiple Hops and Jumps
combo of jumps in place and standing jumps
- repeated movements
- ex) double single leg hop, lateral barrier hop, zigzag hop
Bounds
- exaggerated movements with much horizontal speed
- measured by distance and/or # of reps performed
- Distance >30m
ex) skip, power skip, backwards skip, alternate leg bound
Box Drills
- increased intensity multiple hops and jumps by use of a box
- using one, both, or alternating legs
ex) leg push-off, lateral push-off, side to side push-off, jump on/off, lateral box jump
Depth Jump
- use of gravity and athlete’s weight to increase intensity
- jump vertically and horizontally or to another box
- use one or both legs
ex) single leg depth jump, depth jump to another box, depth jump with lateral movement, depth jump with standing long jump
Upper body plyos
not used as often as lower although still a variety
-good for rapid, powerful upper body movement spots (ex-throwing)
Examples of upper body plyos
Med Ball throw’s and catches (chest pass, two-hand overhead throw, two hand side to side, single arm throw, power drop)
-push-ups (depth push-up)
Trunk Plyos
- stretch reflex is not sufficiently involved during many trunk exercises
- to counteract this exercise movements must be shorter and quicker to allow stimulation of the stretch reflex
Program design factors
Intensity- depends on drill performed
Frequency- 1-3 times per week
Recovery- 48-72hrs b/w session
Volume- repsxsets, # of foot contacts, or distance covered
Program Length- 6 to 10 weeks
Progression- low to moderate volumes of low intensity to moderate intensity to high volume
Warm-up- general warm-up, stretching, specific warm-up
Plyos for young and old
- not a concrete age to start at
- high intensity lower body drills are contraindicated
- progression should be from simple to complex
- min of 2-3 days recovery for youth and 3-4 days for older
- volume and intensity for older should be decreased
Plyos for seniors
-can be done- be careful with depth jumps and one footed contact to to problems with BMD and balance problems
Safety considerations and other problems
insufficient strength/speed/balance/base, inadequate warm-up, improper progression, poor training area, poor equipment, not correct volume or intensity, weight, previous injuries, depth of jump
Strength Base Required
1RM squat at least 1.5x body weight
1RM bench press at least body weight for larger athletes and 1.5x body weight for smaller athletes
-Ability to do 5 clap push-ups
Proper landing technique
centre of gravity in line with base of support
- shoulders over the knees
- flexion of the ankles, knees, and hips
- landing surface should have adequate shock absorbing properties
Safety for depth jumps
no greater than 1.2m
- recommended- 41-107cm
- normal 76-81cm
- for people over 220lbs no greater than 46cm
Speed Base Required
- able to perform 5 reps of squat with 60% body wt in 5s or less
- able to perform 5 bench press with 60% of body weight in 5s or less
Balance Base Required
beginners: 30s single leg
intermediate: 30s single leg in 1/4 squat
advanced: 30s single leg in 1/2 squat
