The Trainability of Adolescent Soccer Players to Brief Periodized Complex Training

Abstract

Purpose: Τo investigate the effect of a complex, short-term strength/power training protocol on performance and body composition of elite early-adolescent soccer players. Methods: Twenty-two players (14-15 years) were randomly assigned to (a) an experimental (EG, n=12, participated in a 5-week training protocol with traditional multi-joint power resistance exercises, Olympic-style lifts, plyometric drills and speed work, four times/week) or (b) a control group (CG, n=10). Strength and power performance [jumping, speed, change of direction, repeated sprint ability, endurance, isokinetic strength of knee flexors and extensors, maximal strength in various lifts, speed-endurance) were evaluated pre- and post-training. Results: Cessation of training for five weeks in the CG induced a marked performance deterioration (~5-20%). Training not only prevented strength performance deterioration but also increased it (~2-30%). Endurance and RSA declined to a smaller extent in EG compared to CG (15% vs. 7.5%). Isometric strength, and body composition remained unaltered in both groups. Conclusions: Results demonstrate that (i) young players exhibit a high level of trainability of their strength/power performance (but not endurance) in response a short-term complex training protocol during early adolescence, (ii) Olympic-style lifts are characterized by increased safety in this age group and appear to be highly effective, (iii) it appears that lifts incorporating a hip thrust result in increased strength of both knee extensors and flexors, (iv) cessation of training for only five weeks results in marked deterioration of strength/power and endurance performance and (v) improvement of strength/power performance may be related to neural-based adaptation since body composition remained unaffected.