Thursday, April 24, 2014

Plyometric Training in Young Players Improves Multiple Markers of Performance

Coaches are constantly looking for better and more economical ways to improve their team’s performance. Often faced with limited training time, it can be difficult to improve fitness, agility, speed and power while also emphasizing the technical and tactical aspects of the game. Recently, fitness trainers have advocated plyometric training as a way to improve sprint speed. However, some have questioned whether this type of training is appropriate and effective for young players. They have also questioned whether plyometrics can improve aspects of physical performance other than speed and power. In a new study published in the Journal of Strength and Conditioning Research, plyometric training is shown to affect explosive actions, endurance and kicking power in young, adolescent players.

The researchers studied two groups of experienced players between the ages of 10 and 16 years. One group utilized a plyometric training program twice per week for seven weeks. This program replaced a portion of their regular technical training. It included high intensity drills, 2 sets of 10-drop jumps from 20, 40 and 60 cm. The control group underwent their regular technical training. After the 20 minute training program, the groups were combined for the remainder of the 90-minute session.

Plyometric training improved several markers of performance. Vertical jump height was increased (4%), especially after rebounding from a 20 cm box (22%). 2.5 km time trial finish time was reduced from 10:36 to 10:12. And maximal kicking distance was increased by nearly 5m, from 32.7 to 37.1m.

As for sprint performance, the control group showed a slight decrease in 20m sprint time while the plyometric group showed no change. Thus, plyometric training prevented the loss of sprint speed that occurred with regular soccer training. Agility was also reduced in the control group but was improved in the plyometric group.

The results show that plyometric training, used twice per week with young adolescent players, can improve several aspects of soccer performance – endurance, agility, power and kicking distance. In addition, sprint speed is also positively affected.

The lack of a positive effect on speed could be a function of the type of training used. Several other studies show that plyometric training increases sprint speed. However, the programs used in these studies included a horizontal component. That is, bounding for distance. This has been shown to increase stride length, which in turn improves sprint speed. In the present study, the vertical component was emphasized. The box or depth jumps used required the players to jump upward after landing, not outward. The researchers mention this and suggest that a more appropriate program for improving sprint speed should include both vertical and horizontal components to the training. That is both bounding and vertical jumping.

The researchers also discuss an important concern regarding plyometric training in young athletes – injury potential. They point out that in their study, as in other studies, no injuries occurred and none of the athletes complained of muscle or joint pain during the training period. Thus, they argue that if plyometric training is done properly, with proper supervision and monitoring of player health, players will respond without added injury risk.

The researchers also point out that their training program can be an effective way to improve both fitness and leg power in teams with limited training time. The time required was 20 minutes, twice weekly. Given that many coaches may only have 2 to 3, 90-minute sessions per week to train their teams, this low-volume, high-intensity method may be an economical mode of training.

Two years ago, we discussed the effectiveness of using plyometric training in young players as a means to improve performance and reduce injury risk. This article adds to that idea by showing that endurance, vertical jump, agility and kicking power can be improved in players 10-14 years of age through this type of training.

Reference

Ramires-Campillo R, Meylen C, Alverez C, Henriquez-Oguin C, Martinez C, Canaz-Jamett R, Andrade DG, Izquierdo M (2014) Effects of in-season low-volume high-intensity plyometric training on explosive actions and endurance of young soccer players. Journal of Strength and Conditioning Research, 28: 1335-1342.