Studied by 2 PeopleTags & Description
Mechanical model of plyometrics exercise
- elastic energy in the musculotendinous components is increased with a rapid stretch and then stored
- if a concentric muscle action follows immediately, the stored energy is released, increasing the total force production
Series elastic component (SEC)
When stretched (eccentric) stores elastic energy that increases the force produced (this is the workhouse and is primarily the tendon)
Contractile component (CC)
Primary source of muscle force during concentric muscle action (Actin, myosin, and cross bridges)
Parallel elastic component (PEC)
Exerts a passive force with unstimulated muscle stretch (epimysium, perimysium, endomysium, and sarcolemma)
Neurophysiological model of plyometrics exercise
Involves potentiation (change in the force-velocity characteristics of the muscle’s contractile components caused by stretch) of the concentric muscle action by use of the stretch reflec
Stretch reflex
The body’s involuntary response to an external stimulus that stretches the muscles
Stretch-shortening cycle (SSC)
- both mechanical and neurophysiological models
- employs both the energy stores of the SEC and stimulation of the stretch reflex to facilitate maximal increase in muscle recruitment over a minimal amount of time
- a fast rate of musculotendinous stretch is vital to muscle recruitment and activity resulting from SSC
- a rapid eccentric muscle action stimulates the stretch reflex and storage of elastic energy, which increase the force produced during the subsequent concentric action
SSC Phase 1
Eccentric
Action: stretch of the agonist muscle
Physiological event: elastic energy is stored in the series elastic component; more spindles are stimulated
SSC Phase II
Amortization
Action: pause between phases I and III
Physiological event: type of different nerves synapse with alpha motor neurons; alpha motor neurons transmit signals to agonist muscle groups
SSC Phase III
Concentric
Action: shortening of agonist muscle fibers
Physiological event: elastic energy is released from the series elastic component; alpha motor neurons stimulate the agonist muscle group
Plyometrics intensity
- the amount of stress placed on muscles, connective tissues, and joints
- controlled by the tupe of plyometrics drill
- as intensity increases, volume should decrease
Plyometrics frequency
- typical recovery time guideline: 48-72 hours b/w plyometrics sessions
- perform two or three plyometrics sessions per week
Plyometrics recovery
- recovery for depth jumps may const of 5-10 s of rest b/w repetitions and 2-3 mins bw sets
- time bw sets is determined by a proper work to rest ration (1:5 to 1:10)
Plyometrics volume
- expressed as foot contacts per workout (or in distance for bounding drills)
- for upper body drills, volume is expressed as the number of throws or catches per workout
Plyometrics beginner volume
80-100 contacts
Plyometrics intermediated volume
100-120 contacts
Plyometrics advanced volume
120-140 contacts
Plyometrics adolescents
Under proper supervision and with an appropriate program prepubescent and adolescent children may perform plyometrics exercises. Depth jumps and high-intensity lower body plyometrics are contraindicated for this pop
Plyometrics masters
- program should include no more than 5 low to moderate intensity exercises
- volume should be lower - include fewer total foot contacts than a standard plyometrics training program
- recovery time plyometrics workouts should be 3-4 days
Plyometrics technique
-proper footwear
- proper landing technique is essential to prevent injury and improve performance in lower body plyometrics
- for lower body plyometrics, it was previously thought that the athlete’s 1RM squat should be at lest 1.5 times her or her body weight
Plyometrics balance
- each test position must be held for 30 seconds
- beginner athlete must stand one long for 30 s without falling
- athlete beginning an advanced plyometrics program must maintain a single-leg half square for 30 seconds without falling
Plyometrics physical characteristics
Athletes who weigh more than 220 pounds should not perform depth jumps from heights greater than 18 inches
Plyometrics landing surface
to prevent injuries, landing surface used for lower body plyometrics must possess adequate shock-absorbing properties (grass-field, suspended floor, rubber mat)
Plyometrics training area
- for most standing, box, and depth jumps, only a minimal surface area is needed
- most bounding and running drills require at least 30 m (33 yds) of straightaway, though some drills may require 100 m (109 yds)
Plyometrics equipment
- boxes should range in height from 6-42 inches
- boxes should have landing surfaces of at least 18 by 24 inches
plyometrics depth jumping
- height = 16-42 inches with 30-32 being the norm
- 18 in or less for athletes who weight over 220 pounds
Speed
The skills and abilities needed to achieve high movement velocities
Change of direction
The skills and abilities needed to explosively change movement direction, velocities, or modes
Agility
The skills and abilities needed to change direction, velocity, or mode in response to a stimulus (decelerate and accelerate again)
Execute movement techniques
Athletes must skillfully apply force
Variables for force relative to the time available to produce force
Rate of force development (RFD) and impulse
Impulse
- change in momentum, either accelerating or decelerating, resulting from a force measured as the produce of force and time
- a basic objective of training is to move the force-time curve up and to the left, generating greater impulse and momentum during the limited time over which force is applied
Rate of force development
The development of max force in min time, typically used as an index of explosive strength
Neurophysiological basis for speed
- nervous system
-SSC
-increased sensitivity of muscle spindles
-Spring mass model
Speed nervous system
Increases in neural drive (aka neuromuscular activity = increase in the rate at which action potentials occur) occur due to strength and plyometrics training and result in increased muscular force production and the rate of force production
Speed stretch shortening cycle
-acutely, SSC actions tend to increase mechanical efficiency and impulse via elastic energy recovery
- chronically they upregulate muscle stiffness and enhance neuromuscular activation
Spring-mass model (SMM)
Sprinting is produced by spring-like actions within the muscle
Increase neural drive
- multi joint movements exploiting elastic-reflexive mechanisms
- emphasize quality and technique, use brief work bouts and frequent rest pause
- heavy resistance training and plyos - complex training
- post-activation potentiation
Sprint speed
Determined by stride length and stride rate; more successful sprinters tend to have longer stride lengths and a more frequent stride rate. These findings suggest that RFD and proper biomechanics are two of the primary limiting factors influencing sprint performance
Running speed training goals
- emphasize brief ground support times as a means of achieving rapid stride rate (requires high levels of explosive strength)
- emphasize further development of the stretch-shortening cycle (higher achievers at top speed sprinting produce high forces in a shorter stance phase using the SSC)
Speed Strength
- transfer of strength improvements to sprinting may require an emphasis on the specificity of training
- this transfer of training effect deals with the degree of performance adaptation and my result from the similarities between the movement patterns, peak force, RFD, acceleration, and velocity patterns of an exercise and the sporting environment
Speed development
- train stride rate over stride length
- assistance training e.g. over speed training (down hill running, rope towing, bungee cored pulls) increases stride rate
- resistance training (sled towing, wind resistance, incline sprinting, sled pushing) improve RFD, largely stride length and some stride frequency
Methods to develop agility
- strength (plyos, lunges, squats)
- change of direction ability - change of direction drills
- perceptual cognitive ability - improve anticipation and decision making time
Perceptual-cognitive ability
- agility activities should begin by adding a perceptual-cognitive component to change-of-direction drills
- ie decelerations or the z-drill can evolve into agility drills through inclusion of a generic stimulus such as a whistle, coach command, or flashing arrow/light
Speed and Agility Program design
- athletes should conduct speed and agility tasks early in a training session
- typically 2-3 sessions per week
- session may be 15 minutes
- rest periods 30s-3 min depending on work time
Plyos for LDR
- improve running economy
- improve muscle/tendon stiffness (via mechanical model)
- increase stride length
- strength an plyos
- repetition continuum
Aerobic exercise economy
- a measure of the energy cost of activity at a given exercise velocity
- an improvement in exercise economy can enhance maximal aerobic power (VO2max) and lactate threshold
- running economy
- tendon stiffness
Running economy training
Plyometrics → resistance → training phase → speed, volume, intervals, hills, etc
Running economy environment
Altitude → heat
Running economy physiology
VO2max → adolescent development → metabolic factors → influence of different running speeds
Running economy biomechanics
Flexibility → elastic stored energy → mechanical factors → GRF
Running economy anthropometry
Limb morphology → muscle stiffness, tendon length → body weight and composition
Running economy
Factors affecting performance in distance runners
Design an Aerobic endurance program
1. Exercise mode
2. Training frequency
3. Training intensity
4. Exercise duration
5. Exercise progression
exercise mode
- the specific activity performed by the athlete: cycling, running, swimming, etc
- the more specific the training mode is to the sport, the greater the improvement in performance
Aerobic training intensity
- high-intensity aerobic exercise increases cardiovascular and respiratory function and allows for improved oxygen delivery to the working muscles (overload principle is important)
- increasing exercise intensity may also improve oxidative capacity of type II fibers
- hear rate (most frequent used method for prescribing aerobic exercise intensity → 60-70% THR up to 75-85% THR (stronger relationship between vo2 and HRR compared to MHR)
Karvonen method
- age predicted max heart rate (APMHR) = 220-age
- heart rate reserve (HRR) = AMPHR - RHR
- Target heart rate (THR) = (HRR x exercise intensity) +RHR
- do this calculation twice to determine the target heart rate range (THRR)
Percentage of maximal heart rate method
- age predicted max heart rate (APMHR) = 220-age
- THR=APMHR x exercise intensity
- do this calculation twice to determine he THRR
Ratings of perceived exertion scales (RPE scale)
- can be used to regulate intensity of aerobic endurance training across changes in fitness level
- may be influenced by external environmental factors
Metabolic equivalents (METs)
- one MET is equal to 3.5 mlkg-1min-1 of oxygen consumption and is considered the amount of oxygen required by the body at rest
- walking 2.5 mph = 3
- resistance training = 6
- walking 5 mph = 8.3
- running 6.7 mph = 10.5
- running 10 mph = 14.5
Power measurement
- cyclists may use power-measuring cranks and hubs to regulate exercise intensity
- metabolic rate is closely related to mechanical power production
Aerobic Exercise duration
- length of time of the training session
- < 70% VO2max for several hours
- > 85% VO2max for 20-30 min
Aerobic exercise program
- progression of an aerobic endurance program involves increasing the frequency, intensity, and duration
- frequency, intensity, or duration should not increase by more than 10% each week
- when it is not feasible to increase frequency or duration, progression can occur with intensity manipulation
Long, slow distance training
- training distance greater than race distance (30 minutes to 2 hours)
- sometimes 2-20 miles
- intensities equivalent to 70% of VO2max
- adaptations from this exercise include the following: increased mitochondrial energy production, enhances the body’s ability to clear lactate, causes an eventual shift of Type IIx fibers to Type I fibers
- intensity is lower than that of competition, which may be a disadvantage if too much LSD training is used
Pace/tempo training
- intensity at or slightly above competition intensity, corresponding to the lactate threshold; 80-90% HRR
- helps improve running economy and increase lactate threshold
-steady pace/tempo training
- tempo run
-intermittent pace/tempo training
Steady pace/tempo training
20-30 minutes of continuous training at the lactate threshold: 15 min warm up, a 3-6 mile tempo run, and 15 min cool down
Intermittent pace/tempo training
Series of shorter intervals with brief recovery periods: 15 min warm up, 8 min hard run, 2 min jog, 8 min hard, 2 min jog, 8 min hard, 15 min cool down
interval training
- exercise at an intensity close to VO2max for intervals of 3-5 minutes. Work:rest ration should be 1:1
- allows athletes to train at intensities close to VO2max for a greater amount of time; >85% HRR
- it increases VO2max and enhances anaerobic metabolism
- interval training should be used sparingly, and only when training athletes with a firm aerobic endurance training base
- interval workout
High-Intensity interval training (HIIT)
- shorter rest than interval training
- uses repeated high-intensity bouts interspersed with brief recovery periods
- several minutes above 90% of VO2max / > 90% HRR
- may be effective for improving running economy and running speed
- an example for long-interval HIIT is >2-3 minutes at 90% VO2max, with relief bouts of <2 minutes
- a short interval may have work periods <45 seconds
- fat loss
Fartlek Training
- less structured than interval; varying work times (similar to a game such as soccer)
- easy running (70% VO2max) combined with hills or short, fast bursts (85-90% VO2max); same as HRR (jog, sprint, jog, sprint, jog, etc) 20-69 min total
- can be adapted for cycling and swimming
- benefits are likely to include enhanced VO2max, increased lactate threshold, improved running economy and fuel utilization
Cross training
A mode of training that can be used to maintain general conditioning in athletes during periods of reduced training due to injury or during recovery from a training cycle (i.e cross country runner swims or bikes)
Detraining
- occurs when the athlete reduces the training duration or intensity or stops training altogether due to a break in the program, injury, or illness
- in the absence of an appropriate training stimulus, the athlete experiences a loss of the physiological adaptations brought by training
- in as little as 2 weeks
Tapering
- reduction of training duration and intensity with an increased emphasis on technique work and nutritional intervention (often reduce volume while intensity and frequency are maintained/helps in recovery and promotes increase in muscle/liver glycogen stores)
- objective of tapering the training regiment is to attain peak performance at the time of competition (most common model is swimming)
- decrease training volume by 60% over 3-4 weeks
- 10-15% every couple days - progressive, linear taper
- 50% immediate decrease - step taper
Aerobic Resistance Training
- benefits may include: improvement in short-term exercise performance, faster recovery from injuries, prevention of overuse injuries and reduction of muscle imbalances
- it can improve hill climbing, bridging gaps between competitors during breakaways, and the final sprint
Aerobic altitude training
Periodization
A theoretical and practical construct that allows for the systematic, sequential, and integrative programming of training interventions in mutually dependent period of time in order to induce specific physiological adaptations that underpin performance outcomes
- variation in volume in intensity to optimize gains
General Adaptation Syndrome (GAS)
Alarm
Resistance
Exhaustion
one of the foundational concerts from which periodization theories have been developed
Alarm phase
Initial phase of training, when stimulus is first recognized and performance generally decreases in response to fatigue
Resistance phase
Second phase, in which adaptation occurs and the system is returned to baseline or, in most instances, elevated above baseline
Super compensation phase
New level of performance capacity that occurs in response to the adaptive response found in step 2
Overtraining phase
If stressors are too high, performance can be further suppressed and overtraining syndrome can result
Stimulus-fatigue-recovery-adaptation theory
- an extension of the GAS suggesting that training stimuli produce a general response
- the greater overall magnitude of a workload, the more fatigue accumulates and the longer the delay effort complete recover so that adaptation can occur
- the greater intensity/duration of stimulus, the greater the recovery period must be
- involutivos or detraining occurs if no new training stimulus is introduced
Fitness-fatigue paradigm
- training results in both fitness and fatigue
- high training loads result in both elevated fatigue and fitness levels. If loads are too high and fatigue exceeds fitness, preparedness will decrease
- low training loads result in minimal fitness or fatigue
- important to vary training loads
- fatigue dissipates faster than fitness allowing for elevated preparedness with use of appropriate training strategies
Macro cycle
Typically an entire training year but may also be a period of many months up to four years (Olympic athletes)