When it comes to endurance, fatigue, and repeated sprint ability, the benefits of creatine isn’t yet conclusive. But based on a previous study that found creatine to help female soccer players increase strength and lean tissue during off-season training, the researchers in this current study hypothesize supplementation may benefit the endurance of female soccer athletes more when paired with plyometric (jumping) exercises.
“The objective of this study was to investigate the effects of a six-week plyometric training and creatine supplementation intervention on maximal-intensity and endurance performance in female soccer players,” the researchers wrote in their study, published in this month’s Journal of Science and Medicine in Sport.
After the course of the study, they found that without having to add extra time to usual soccer training but replacing some drills with specific plyometric training plus creatine supplementation, the maximal-intensity and endurance performance of the soccer players increased.
Thirty amateur female players between the ages of 19 and 28 (three goalkeepers, nine defenders, ten midfielders, and eleven forwards) participated in this study. Part of the participation requirement was that the athletes should have never before taken creatine supplements.
The players were also selected by changes in a vertical jump performance and results of a short-term plyometric drill during recruitment, to make sure that all study participants have similar training loads and competitive backgrounds.
Random assignment divided players into three different groups: A plyometric training group receiving placebo of glucose, a plyometric training group receiving 20g/d creatine (using the brand GNC Pro Performance), and a control group with no plyometric training also supplemented with placebo glucose.
Jumps, sprints, and shuttle run tests
All participants were directed to ingest their supplements divided into four equal doses over the course of one week during loading week at breakfast, lunch, dinner, and before bedtime. For the five weeks after, supplements were ingested by single daily doses of 5 g with lunch. Participants were also instructed to maintain their usual dietary habits.
Creatine (or the placebo) was dissolved in “juice that contained a small amount of carbohydrates to reduce creatine muscle uptake,” the researchers wrote.
One week before the creatine or placebo intervention, participants were introduced to the plyometric drills, and measurements were taken. The exact same procedure was repeated one week after the maintenance period. Drills used for measurement were also incorporated into the participants in the plyometric groups’ usual training schedule which overlapped the study.
These drills, scheduled across three days a week, included squat jump, countermovement jump, 20-minute sprint test, running anaerobic sprint tests, shuttle run tests, peak jump power tests, and change-of-direction speed tests, among other things.
Soccer training and creatine
“Our results suggest that replacement of some soccer drills with specific plyometric training, with no additional training time during (in-season) competition, is an effective training strategy for increasing maximal-intensity and endurance performance in female soccer players,” the researchers wrote.
“Furthermore, our results demonstrated that creatine supplementation during plyometric training may boost further adaptations related to maximal-intensity exercise and repeated sprint ability,” they added.
They found that the 10 participants in the creatine group experienced a body mass increase of 1.4% despite unchanged dietary intakes (which was also logged for the study by the participants). The researchers suggest that it is an acute effect of creatine supplementation, because a similar study showed increases in female soccer player body mass after seven days of supplementation.
They also found that both plyometric groups improved sprint performances, change-of-direction speeds, and endurance at the end of the intervention, but the control group was unchanged. However, the creatine group showed a “meaningful increase in peak jump power load,” they wrote.
The creatine supplemented group showed a greater increase in 40-cm drop jump reactive strength index, peak jump power load, and squat jump performance.
“In practical terms, creatine supplementation may be seen as an ergogenic aid while applying plyometric training in adult female soccer players, at least when the target is improving specific physical performance,” they concluded.
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Source: Journal of Science and Medicine in Sport
Published online ahead of print, doi:10.1016/j.jsams.2015.10.005
Effects of plyometric training and creatine supplementation on maximal-intensity exercise and endurance in female soccer players
Authors: R. Ramírez-Campillo, et al.