Saturday, 1 December 2007

Strength training in volleyball: Periodization and other issues

Professional volleyball is becoming more and more demanding from a physical standpoint. The number of competitions is increasing and elite players are involved in those all-year-round. In fact, players involved in club championships and national team tournaments play a very high number of matches and have very few rest periods during the year. We could say that the sporting season for those individuals is never-ending. If we also consider top clubs, we can easily see that during the last years the number of matches increased. This is due to the fact that top teams are not only involved in playing the national championship, but also in national and European cups. This increased demand is of course changing the way physical conditioning was done before. Nowadays there is a need for a correct planning of the activities, travels and rest periods in order to be able to avoid overuse injuries, overtraning and underperformance. The key for being able to prevent all of the above is a very well planned periodization, which needs to be monitored on a weekly basis and corrected during the season. Before planning any type of program it is important to be aware what are the physical demands of the game. Some players play different positions and so have different needs (i.e. Libero, Setter and Opposite). Then, it is important to establish individual characteristics (and performance level). In this connection it should be pointed that appropriate tests should be utilised in order to gain information which could be useful in the development of the training program itself. The training programme should then be individualised based upon each player's individual characteristics.

The periodization plan has to take into account the official and friendly matches, the rest periods and the total number of training sessions.

Strength training sessions can be planned during the competitive season if a proper work-to-rest planning is performed. Testing and training monitoring is extremely important, since it is the only way to determine adaptations and prevent overtraining syndrome or underperformance. By controlling adaptations we are in fact able to re-evaluate athletes’ level of performance and then we can change the training methodology, the exercises and the program itself and be able to have further improvements.

With this in mind, before coming to some practical examples, it is important to re-consider some of the concepts behind periodization.

Strength training, periodization and volleyball

Strength training should be implemented in volleyball not only to improve jumping ability and spiking velocity. Volleyball performance is characterised also by the ability to maintain a good balanced position when receiving and passing the ball, performing a dig or a block and sustaining the impact of fast balls with the upper body. Strength training should be then directed and focused not only on the lower limbs but also on the upper limbs and the trunk most of all to avoid injuries, but also with the view of improving some specific technical skills.

Most of the research studies published in the literature have been carried out using physical educations students, untrained people or recreational players, and we all know that training an elite athlete is a different issue. The higher the level of the athlete, the more difficult is produce enhancement of performance. However, the principles presented in this blog article could be extended to all type of volleyball players.

Before discussing periodization, it is important to remind what are the effects of strength training exercises. The adaptation to the training stimulus is related to the modification induced by the repetition of daily exercise, and is specific for the movement executed (Edington and Edgerton, 1976). These adaptations are related to the fact that human skeletal muscle is a specialized tissue which modifies its overall function capacity in response to chronic exercise with high loads (McDonagh and Davies, 1984). The above mentioned findings all suggest that resistance exercise can be an effective means for enhancing neuromuscular performance. In this connection it should be noticed that changes within the muscle itself constitute the most important adaptation to resistance exercise (Sale, 1988; Behm, 1995). In fact, strength training response has been shown to be mediated by both neurogenic and myogenic factors (Moritani and De Vries, 1979). Neural adaptations have been indicated as the first changes occurring in the muscle, permitting gains in muscle strength and power in the early stages of a resistance exercise program in the absence of increase in cross-sectional area of the muscle (Behm, 1995; Costill et al. 1979; Sale, 1988). It has been also demonstrated that specific adaptations occur depending on the training program implemented (Sale and Mc Dougall, 1981). Strength training then, can be considered a training stimulus which produces specific adaptations on human skeletal muscles, based upon the protocol utilized for training. The specificity effect of strength training has been underlined by many authors (Sale, 1988; Behm, 1995; Morrisey et al. 1995; Bandy et al. 1990) and the velocity specificity effect has been suggested as one of the most interesting outcome of resistance exercise programs. However, even if the mechanisms underlining this velocity-specificity effect have not been clearly defined, most importance has been given to neural adaptations such as improved coordination, increased activation of prime movers muscles (Moritani and De Vries, 1979) recruitment and synchronization.

It appears then clear that with strength training the neuromuscular system is able to perform to a higher level. It is also clear that several neurological mechanisms are involved in the early gains, with hypertrophy being the last step of the adaptations process. Strength training impacts several systems, in fact endocrine, skeletal, metabolic, immune, neural and respiratory acute and chronic responses have been observed following single bouts or repeated bouts of strength training.

With this in mind we have then to say that the careful selection of the training variables (volume, intensity, density and exercises) determines the effectiveness of the program. Exercises should be chosen based upon the possibility of transfer in competition-specific motions. The parameters to control such outcome are very simple: muscle-joint mechanics and muscular activation timing.

Let’s consider the first one. In volleyball one of the most important actions is the volleyball spike. This technical motion is performed with a stretch-shortening cycle of the leg’s extensors muscles. We know the muscles involved in such motion and we know the mechanics (stretch-shortening cycle). We also know that this motion is a closed chain-type of activity. Hence, when choosing the exercises the movement patterns should mostly be characterised by closed-chain-type of activities which simulate similar mechanics.

Let’s now consider another aspect: timing of muscle activation. The jump and spike action in volleyball, depending upon the technique utilised, is performed with lower limbs muscles performing mechanical work for a duration ranging from 300 to 450 milliseconds (Bosco, 1985; Coutts, 1982; Viitasalo, 1982). Similar times were also measured in 1 legged spike actions Huang et al. (1999). Specific exercises should also be included in the training plan repeating timing and patterns of activation.

Now then, we know that general strength training is good for enhancing neuromuscular performance and that adaptations are stimulus-specific. We also know that the specific performance demands are related to the capability of an athlete to express maximal power in limited amount of time.

Let’s now discuss periodization in elite volleyball. It is important to say that the earlier model developed by Matveyev and presented in most books of training methodology should be considered only as a pedagogical model, and not as a real model to be based on. Most of all, it should be pointed that most of the periodization models have been developed for individual sports and cyclic activities (running, rowing, cycling) and there is at the moment no model available for team sports demands. So, we should re-consider all the information which is available on this topic. From a pedagogical standpoint some concepts of periodization are important.

It is in fact the definition of specific work to rest ratios, volume undulations, and intensity undulations, that defines effective training cycles. However it should be pointed out that what is good for a team cannot be good for another one, since there are different individuals and different athletic levels. This means quite frankly that it is impossible to have an "optimal model". There are however general concepts which are useful for developing an effective periodization model.

In most American books periodization is divided into 3 phases: preparatory, competitive and transition phase. We know that nowadays top volleyball players have a very long competitive season and a very short preparatory and transition phases. Lower level players of course have the luxury of time and could spend more time in preparation and/or transition. If we look at the typical playing patterns of international players and the typical club and national team calendar of elite European nations we can see how some players move from Club activity to an intense summer of International activity to then start again in the Club with minimal time for recovery and almost no time to train before getting involved in further competitions.

In many books an optimal progression is suggested for strength training: anatomical adaptation phase, hypertrophy phase, maximum strength phase, conversion phase and maintenance phase. Those concepts are of course based upon the structure of the sport season in USA where the competitive season is relatively short as compared to Europe and there is a lot of time for preparing the season itself, with almost no time during the competitions.

I take the liberty to state that this approach is wrong in European sporting seasons in most team sports. For sure, be able to go through all of the above mentioned phases, we should have enough time. We all know there is no time (and this is not a bad thing sometimes…). Hence, the solution is a different approach to strength training.

In this approach approach, maximal dynamic and explosive-type loads have to be used concurrently, in order to gain force and power at same time. Of course a good planning should change during the season the percentage of volume dedicated to one or the other, but during the whole season both have to be trained. The key for understanding when and if it is time to change something in the training program is testing.

Adaptations to strength training programs depend on the type of muscular activation, intensity and volume (Sale & Mac Dougall, 1981; Atha, 1981). We know in fact that training strength utilising heavy loads and low contraction speed determine enhancement of maximal dynamic strength (Berger, 1962; Hakkinen, 1994). However, it is important to say that in order to produce enhancement in power and explosive-type motions, those loads have to be lifted with the highest possible speed and lighter loads have to be utilised as well (Berger, 1963; Hakkinen, 1994; Kaneko et al., 1983; Moritani et al. 1987). The combined methodology has been shown to be productive in enhancing a wider spectrum of the force/velocity capabilities of skeletal muscles (Harris et al., 2000; Newton & Kraemer, 1994; Stone, 1993; Stone et al. 1980).

The characteristics of the explosive-power exercises must be short duration (200-300msec) and high intensity. An example of the different activation patterns are presented in Figures 1 and 2. In this case a professional female volleyball player was performing half squat with 70% of 1RM and drop jumps from a box 40cm high starting with knee bent at 90°. Here it is possible to see the different EMG activity and the duration of the mechanical work. This is an example of the different timing and muscle activation patterns in different exercises. Again, this is a support of this “muscle tuning” approach to strength training. The aim is to permit to the neuromuscular system to express its maximum in a working time spectrum which is the characteristic of the performance demand. So, when choosing the exercises and developing a program, always there is a need of using combined exercises (maximal dynamic strength and explosive strength).

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Figure 1. Half Squat with 70% of 1RM load. Biomechanical Analysis

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Figure 2. Drop Jump. Biomechanical Analysis

Concluding remarks

It is impossible to have a specific model for planning a season in team sport. The periodization plan should take into account the level of the team, the competitions, the number of the players available, the travelling schedules and many other aspects. Most of the times, what is planned at the beginning needs to be changed, due to the results and participation to different competitions (European Cups, Play-offs…). It means that the only way to try not to make mistakes leading to overtraining or underperformance is to test routinely the players and adjust the programme allowing appropriate rest-to-work ratios. Of course it is important in the pre-competitive phase to increase the training volume to build up maximal dynamic strength mostly and endurance to the game throughout game-like drills. Then, it is possible to increase intensity, increase the amount of explosive-type exercises and put more emphasis on speed-strength drills. Rest is important, if your players have enough rest they will perform always well not only in competition but also when intense technical and tactical sessions are planned. Sometimes it is better allowing one or two days off rather then exaggerating with training sessions. One main rule: if the players are tired, the best training is rest and recovery!

In the following figures there are examples of the training load (always referred only to the strength training sessions) of professional female volleyball teams participating in various competitions. As you can see two teams with two different load distributions can still improve vertical jumping ability. In one case at a certain time of the season due to a high density of competitions, the training load was lowered to maintain the level reached and avoid overtraining. In the second case, a different approach was used since the goals and the characteristics of the team were different.

These are only examples of how to manage and plan the season. The most important aspect to remember is that without a proper testing and monitoring procedure you would never be able to understand if the plan is effective or not and most of all, in which direction adaptations are going (are the players gaining strength, power or both?). Without this approach, training becomes just a blind guess which is unlikely to produce performance gains.

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Figure 3. Training load and vertical jumping ability in a professional volleyball team participating in the Spanish League, Spanish Cup and European Champion's League (average values n=10)

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Figure 4. Training load and vertical jumping ability in a professional volleyball team participating in the Italian League and Italian Cup (average values n=10)

1 comments:

Carl on 7 December 2010 at 23:19 said...

Amazing to know that the Professional volleyball is becoming more and more demanding,and the information about the strength training is useful to read.



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