An outline of speed strength development, looking at traditional
weight training methods, time controlled speed strength development and
plyometrics. The text is an extract from the author's Level III qualification
dissertation under the Australian Track and Field Coaches Association's coaching
scheme. Although written for young discus throwers, the speed strength
development aspects are applicable to most power
Speed strength is the ability of the neuromuscular system to produce the greatest possible impulse in the shortest possible time. The two aspects to speed strength are starting strength and explosive strength. Starting strength is the force developed in 30ms from the start of a concentric contraction. Explosive strength is the ability to continue the initiated force as fast as possible. The time period is approximately 150ms. It is the maximum rate of force development (RFD) in a maximum isometric contraction.
Types of exercises
Olympic lifts (snatch and clean) and their derivatives have potential for power outputs higher than the so-called "power" lifts (squat, bench press, deadlift). Other exercises such as bench press throws (using Smith machine) and multiple repetition jump squats may provide an excellent alternative or supplement to the traditional Olympic weightlifting style movements for the development of speed strength and for athletes of lower strength levels. The power produced during jump squats or bench press throws can actually exceed that of the Olympic lifts.
For effective speed strength development a loading of 80-90% of 1RM (2-5 reps) is recommended for Olympic lifts whereas for bench press 50-60% of 1RM is desirable. For the jump squat 30-40% of maximum may be more appropriate. The percentage for jump squats must take into consideration the athletes body weight.
For example, a 100kg athlete with a 1RM squat of 180kg has (total system weight 280kg) x 40% = 112kg (only 12kg above body weight). Jump squats for this athlete need only be done with 12kg loading.
|Rest between reps. (sec.)||Speed reduction 10%
Reps per set in prep phase
|Speed reduction 5%
Reps per set in com. phase
|0 (i.e. rhythmical)||5||3|
The advice from Professor Tidow is that the sequence of HM, NAM, TCSSM can be repeated three times annually as follows:
1. 4-6 weeks of hypertrophy methods (up to 8 weeks is permissible if the athlete requires muscle mass)
2. 3-4 weeks of neuronal activation method.
3. 3-6 weeks of time controlled speed strength methods.
In the week before a major competition TCSSM once only could be enough, three days before competing e.g. lift on Wednesday, compete Saturday.
Plyometric training causes an increase in maximum rate of force development. Verkhoshansky suggests that traditional weight programs which incorporate plyometrics are superior to those that do not include plyometrics. The Russian and Bulgarian speed strength methods mentioned earlier employ plyometrics in the complex.
Plyometrics is a familiar term amongst athletes and coaches and has been defined as exercises that enable a muscle to reach maximum strength in as short a time as possible. This speed strength ability is known as power.
Other definitions include: "Powerful muscular contractions after rapid stretching or dynamic loading of the same muscle group" and "Quick powerful movements that involve a pre-stretch of a muscle just before its contraction." (Pezzullo) Another term for this type of muscle action is the stretch-shortening cycle.
Muscle elasticity is an important factor in understanding how the stretch-shortening cycle can produce more power than a simple concentric muscle contraction. The muscles can briefly store the tension developed by rapid stretching so that they possess a sort of potential elastic energy.
To use this stored energy and to achieve maximum results with plyometrics the concentric contraction must immediately follow the application of load and the preceding eccentric contraction should be of short range and rapid. In other words the faster a muscle is stretched the greater its concentric force after the stretch. The result is a more forceful movement for overcoming the inertia of an object e.g. a 1 kg discus. Throws coaches will often refer to pre-stretching or pre-tension e.g. pre-tension across the chest prior to delivering a discus. The period during which the muscle changes from an eccentric to a concentric contraction is called the coupling time and the greater force developed is associated with the shortest coupling time. Bosco et al (1982) proposed that individuals with a high percentage of fast twitch fibres in the leg muscles exhibit a maximum plyometric effect when the eccentric phase is short, movement range is small and coupling time is brief.
On the other hand, subjects with a high percentage. of slow twitch fibres produce their best jumping performance when the eccentric phase is longer, movement range is greater and the coupling time is longer. Also the degree of flexion of the limb (e.g. knee when doing single leg hops) should not be too excessive because the larger the eccentric movement the greater the loss of elastic tension. The rate of stretch rather than the magnitude of stretch determines the extent of elastic energy boosting that the muscle receives following an eccentric contraction. (Hennessy).
The stretch reflex is another mechanism integral to the stretch-shortening cycle and is of importance to throwers. The stretch reflex responds to the rate at which a muscle is stretched and is faster than other reflexes. A voluntary response to muscle stretch would be too late to be of any use to a thrower.
Hopping, skipping, jumping, bounding, depth jumps and medicine ball rebounding are exercises commonly used in plyometrics. Cones, hurdles, stairs, benches and boxes of various heights also are used.
Depth jumping is not recommended for the young athlete because of the large forces exerted. 1 believe depth jumps are often the reason for avulsion fractures in young athletes. The young or beginner athlete should begin with less intense exercises such as hopping, skipping and bounding, progressing to jumps over low hurdles and then lead up to the high impact exercises of depth jumping after some years of conditioning.
By Denis Knowles -- from Modern Athlete and Coach