Our Research Review Article for today comes from the January 2011 issue of the Journal of Strength and Conditioning Research (Rubley, et. al., 2011). This study assessed an intervention of low-level plyometric training on vertical jump and kicking performance in two groups of thirteen-year-old female soccer players.
“High intensity plyometric training is often used by strength and conditioning coaches to increase power in mature athletes. However, because of the concern that high-intensity plyometric training will result in injury in skeletally immature athletes, this valuable training mode is often not used with adolescent athletes.” (1)
In our opinion, this study hit on some great points…
- “Significant improvements” in athletic, power driven activities can be achieved with low intensity plyometric training in a youth setting.
- Low intensity plyometric preparatory training can be a “safe and effective alternative” to traditional plyometric training.
- Training to improve power in simple jumping, hopping and cutting drills can transition over into more functional, sport specific skills.
This 14-week study was broken into two, six-week blocks.
|Weeks 1-6||Single Legged Cone Hops (10 cones)||Forward||1 set||5 reps|
|Single Legged Hurdle Hops (10 Hurdles)||Forward||1 set||5 reps|
|Single Legged Hurdle Hops (10 Hurdles)||Lateral||1 set||5 reps|
|12” Box Shuffles (1 box)||Lateral||4 sets||20 reps|
|Mid Season Test|
|Weeks 8-13||10” Box Jumps||Forward||3 sets||10 reps|
|10” Box Depth Jumps||Forward||3 sets||10 reps|
|Cutting Drills Around Cones (5 yds apart)||Diagonal||2 sets||10 reps|
In our plyometric progression, we start with an emphasis on positioning and body control and then progress slowly into low frequency, low impact plyometric preparatory drills that begin to teach the athletes to move with rhythm and elasticity. Eventually, they become strong enough to put more force into the ground, and because they have such a strong foundation in athletic movement and positioning, these drills naturally become more “plyometric” in nature.
We begin with a focus on squat and lunge positioning, where we teach the athletes to position themselves in such a way that they “feel” more powerful (able to execute the movement with more fluidity, rhythm and speed). Next we progress to jumping, landing, and hopping drills while also blending in a more athletic crossover type movement that we feel teaches the athletes how to control their body position in the deceleration to acceleration transition that shows up in most agility programs.
We then move into box and stair step up or step up jumping motions and begin to move with speed and confidence. At this point they are have already started to see results on the field in speed, strength and power related athletic movements, and we now can begin to teach the low level, elastic precursors of plyometric exercise.
The results in this study were very comparable to what we notice in our training programs. The Vertical Jump (which is an accepted way of measuring lower body power) improved by 18% over the 14 week season in the group that performed the plyometric intervention one time per week, while the control group’s vertical jump actually decreased by the end of the 14 weeks.
- Plyometric Group Pre-Test = 39.6 cm Post-Test = 47.0 cm
- Control Group Pre-Test = 39.4 cm Post-Test = 36.8 cm
In regards to kicking distance the plyometric group improved by 21.5% while the control group’s kicking distance decreased by 15.6%.
- Plyometric Group Pre-Test = 25.9m Post-Test = 33.0m
- Control Group Pre-Test = 27.6m Post-Test = 23.3m
The athletes in this study had never before been trained in any plyometric type activity and they all had at least 4 years of club soccer experience. This tells us that the results in kicking distance were most likely not from technical training in practice. The decrease in performance in the control group reinforces this assumption as both groups were trained in the same environment in regards to technical skill.
Although our training with athletes in this age group varies slightly from this study, the take home remains the same… Young athletes who are lucky enough to train in both the Physical and Technical / Tactical side of the Pyramid of Sports Mastery (shown here) are more likely to improve their performance. Isolated focus in a technical / tactical environment does not provide the young athlete with the broad foundation necessary to execute tasks that require speed, strength, and power.
- Rubley, M.D., Haase, A.C., Holcomb, W.R., Girouard, T.J., & Tandy, R.D. (2011). The effect of plyometric training on power and kicking distance in female adolescent soccer players. Journal of Strength and Conditioning Research, 25(1), 129-134.