Power is the rate at which mechanical work can be performed, or the rate at which energy is expended in a physical process. It is the measure of how much physical energy is created in each second that passes. the size of the force applied, and the velocity at which it is applied.
Power = force x distance/time
Power is a measure of the force being appliued at speed, and therefore, is a valuable measurement in sports requiring fast, dynamic movements, such as sprinting, jumping, throwing, weightlifting, and most field sports.
PLYOMETRICS : Plyometric exercises are based on the understanding that a concentric (shortenning) muscular contraction is much stronger if it immediately follows an eccentric ( lengthening ) contraction of the same muscle. Plyometric exercises develop this stretch/reflex capacity in a muscle. With regular practice, muscle fibre should be able to store more elastic energy, and transfer more quickly and powerfully from the eccentric, to the concentric phase.
You should ensure adequate pre-conditioning, and progress should be incremental. Weight training is an excellent means of pre-conditioning, and can be combined with plyometrics for a heightened fast-twitch response.
When selecting the right plyometric exercises, you must consider the specifics of your sport, athletes maturity, level of pre-conditioning, and ability to pick up the complexities of the skill. For example, single leg moves are more advanced than double leg moves. Squat jumps are much easier than bounding for 20 metres.
PLYOMETRIC DRILLS RANKED BY INTENSITY :
Tuck jumps, split jumps, squat jumps = low intensity
Standing long jump, standing hop, standing jump for height = low – medium intesity
5 consecutive bounds, 2 x 6 bunny jumps, double foot jumps over 4 hurdles, double foot jumps up steps = medi6 jumps – down and upum intensity
3 x 2 hops and jump into sand, put with 11 stride approach, or 2 x 10 bounds with a 7 stride run up, or 2 x 6 jumps – down and up = high intensity
Run to hop off a low box onto one leg landing, followed with 3 subsequent hops, or bounding uphill = very high intensity.
Hop and hold 5 times = high intensity
Bound/hop/bound/hop and hold over 30 metres = high intensity
*To perform the above two examples, the athlete literally stops on each landing, before springing into the next move where required.
Drop and hold from height above one metre = very high intensity.
Novices should start with low intensity exercises. Wear well cushioned shoes, and perform the drills on a yielding surface, such as a running track, or a spring floor.
ECCENTRIC DROP AND HOLD JUMPS :
Utilized since the 1960’s. Eccentric drills focus on the plant and absorption phase of a dynamic movement, and forego the concentric phase in the stretch/reflex sequence. Advocated because of their huge force absorption potential, and as a further stretch/reflex conditioner. Eccentric training will make you sore, but you will get used to it. Downhill running is also good eccentric training. Periodise your plyometric training.
PERIODIZATION PLAN :
PRE-SEASON /EARLY CONDITIONING PHASE :
Split squats, jump squats, straight leg jumps, can all be incorporated into a circuit. High reps, short recoveries. They will develop low-level power, and general sports specific movement pattern conditioning, plus specific endurance. If you are an endurance athlete, you could continue this kind of training beyond your pre-condition phase, and integrate it into your non-track/rowing/cycling sessions. Runners could also incorporate plyometric drills into Fartlek- type workouts.
MAIN POWER CONDITIONING PHASE
Use drills from the medium intensity categories. Runners should progress to single-leg variants, as these are most relevant to their sport. Do not neglect lower-leg drills, such as straight leg jumps – where the athlete literally bounces up and down on the spot. These will improve calf and achilles tendon power, leading to optimum foot strike, and force return when running. Middle and long distance runners could incorporate bounding and hopping into the warm-up stage of their track sessions; also hill training to develop running specific power, while also continuing plyometrics in their circuits.
PRE – COMPETITION PHASE
Concentrate on quality drills that replicate the speed and movement patterns of their chosen sport. Select high intensity drills, but don’t let fatigue affect technique, so in other words, ‘quality over quantity’.
COMPETITION PHASE
The competition itself will act as the prime conditioner, but in the lead up to the event ( up to 7 days before competing ) you should perform high quality plyometric drills in low numbers. Endurance athletes could continue with medium/high intesity quality drills as part of their warm-up, or as part of their low intensity workouts.
VOLUME AND INTENSITY GUIDELINES
Volume of jumps in each session depends on intensity and goals. For jumps on the spot, or standing, measure volume in terms of foot contacts.
Beginner : pre-season 60-100 foot contacts @ low intensity in one workout.
Intermediate : pre-season 100 – 150 @ low intensity, plus 100 moderate intensity in another workout.
Advanced : pre-season 150 – 200 @ low/medium intensity in one session.
Intensity is the key. The more dynamic the move, and the greater the power generated, the fewer foot contacts are required. As training phases progress, maintaining quality is crucial, and the number of foot contacts should be reduced, as optimum power and speed need to govern performance. Bounding and hops are best measured in terms of sets and repetitions, distance covered, and whether they are performed from a standing start, or with a run-on. For example, a maximum 5-10 bounds per set into a session, with 50 – 75 ground contacts. If a run-on is used, the number of reps should be reduced.
Avoid fatigue. Rest between sets 1 – 2 minutes. Successive depth jumps should be separated by intervals of 15 – 30 seconds, or even longer, if very intense multiple jumps and hops are being performed. These recovery intervals will allow the stretch reflex mechanism to fully recover. Two to three sessions a week, but not on consecutive days, or 7 – 10 days prior to an event. Newcomers may experience an initial decline in performance until they become accustomed to the training.
The stimulation and adaptation of the nervous system is the key to producing and improving speed and power. Power athletes need lots of well trained fast-twitch muscle fibres, producing high forces at high velocities, which are recruited not only in training, but also in competition. To do this, they must train at high intensities to produce the required nervous stimulation and subsequent nervous and muscular adaptation.
Too often, the worth of a training session is measured in terms of the amount of time the session lasted, or feelings of ‘muscle burn’ or breathlessness. But what really counts is the intensity of each individual movement.
Power is quite distinct from strength. In simple terms, power is the ability to generate force quickly. It is defined mathematically as force x velocity. High levels of power will occur in the mid-range of either force or velocity. If an athlete develops greater power, this in turn enhances his ability to generate both force (strength) and velocity (speed). This combination of both speed and strength may be more useful for athletic performance than strength alone. Novices will increase power, and their ability to generate more force at fast speeds simply by increasing strength (1 rep maximums). Indeed, research shows that maximum strength is strongly correlated with power, especially in less experienced athletes. This endorses traditional heavy weight training ( 75 – 95% 1rm ) as a way to improve athletic performance. However, once an athlete has reached a high level of strength, any increases will lead to improvement only at the high force/slow velocity end of the curve. This means no increases in power or force at fast speeds, which is not desirable for most athletic movements.
By contrast, ‘ballistic’ training has proven to increase power and rate of force production, and is more highly correlated with athletic performance than strength training. Plyometric jumping or throwing exercises tend to use higher velocity and lower force, whereas Olympic lifting – eg, power cleans, use higher force and lower velocity. Between these two extremes lie ballistic weight exercises, such as barbell squat jump, and bench press throw, which employ moderate forces and velocity.
Plyometric exercises promote high movement speed, fast-twitch fibre recruitment, and elastic tendon energy release.
Olympic lifts involve very high power outputs, high rates of force production, and increases in muscular coordination of whole-body movements, such as combined ankle, knee and hip extension.
Ballistic weight exercises are very useful for developing high power in specific areas of the body, such as arm extension power with bench press throws, and will result in high rates of force production and muscle activity in the specific muscle groups involved.
Power is highly correlated with level of performance, and training which develops the maximum power output will increase force levels at the mid to high velocity end of the force – velocity curve. Recommended exercises are power snatch, power clean, barbell squat jump, bench press throw, and heavy bag rotation throw. These are all functional movements requiring moderately heavy loads moved as fast as possible. These exercises involve more power output than plyometric jumps, which use no additional load, or medicine ball throws, which are relatively light. Maximum power training is a distinct discipline, and should be performed in addition to plyometric training, not instead of it.
Research has shown that the maximum power produced on a bench press throw, or a squat jump occurs with loads of around 50 – 60% of 1RM for the bench press or squat exercises. To develop maximum power levels in the legs and upper body, you can use 1RM test scores to determine the power training loads.
When performing a maximum power workout, 3 – 5 sets of 3 – 5 reps per exercise is effective. Power training must be high quality, as the aim is to recruit fast-twitch muscle fibres. For this reason, it is important to take at least 3 minutes rest between sets, and to focus on moving the bar as quickly as possible. Maximum power training performed at less than maximum power simply doesn’t work; coaches must encourage their athletes to hit each lift with maximum effort, while athletes must learn to focus on high quality execution of the exercises. Power training is not like endurance training, where it is enough just to complete the workout; it is how well you train for power that makes the difference.
With the Olympic lifts, such as power snatch and power clean, most power occurs at slightly less than the maximum load. Around 85% 1RM; 2 -4 sets of 2 – 5 reps with long rests is best.
Many athletic movements, especially throwing and kicking, involve trunk rotation. Rotational movements are not possible with barbells or weight machines, but standing rotational throws of a heavy bag ( 15 – 30kg depending on the strength of the athlete ) are very effective at producing maximum rotational power, as they involve greater muscular force than medicine ball exercises. Same sets, reps, and rest as above are recommended.
SUMMARY
The main difference between traditional heavy weight training and power training lies in the load and speed of the exercises. Loads of 75 – 95% 1RM will result in increased maximum strength, while loads of 50 – 60% 1rm performed ballistically, will result in increased maximum power. Once an athlete has reached high strength levels, maximum power training may be more conducive to peak athletic performance than further increases in maximum strength.
As a guideline, elite levels of strength for a male athlete are 1rm squat of 2.5 – 3x bodyweight, and 1rm bench press of 1.5 – 2x bodyweight, while those for a female are 2.0 and 1.5x bodyweight respectively. Once these levels have been reached, any athlete would probably benefit more from maximum power training than strength training. It is best to combine the two methods within a periodised program. A phase of maximum strength training, followed by, or combined with a phase of maximum power training would seem best practice.
Some researchers support the combined use of maximum strength training for power development. For example, high intensity weight training for increased rate of force development, with results as transferable across the whole range of the force velocity curve, as they are for novice athletes.
Maximum strength is a precurser to power, and needs to be developed to a sufficient level to maximize power production, particularly in stretch – shorten cycle movements.
Athletes who wish to continue to benefit from training programs must vary their training. By incorporating both maximum strength and maximum power training into a training cycle, or periodization, athletes can present their neuro-muscular systems with a variety of different stimuli, thus enhancing the adaptations.
Athletes must learn to make maximum efforts, recruiting as many muscle fibres as possible. It is also important to ensure sufficient recovery between workouts, and to plan maximum power training sessions at times when they are fresh and capable of high quality lifting.
