title: Effects of in-season short-term plyometric training program on leg power, jump- and sprint performance of soccer players.
abstract: Our hypothesis was that the addition of an 8-week lower limb plyometric training program (hurdle and depth jumping) to normal in-season conditioning would enhance measures of competitive potential (peak power output [PP], jump force, jump height, and lower limb muscle volume) in junior soccer players. The subjects (23 men, age 19 ± 0.7 years, body mass 70.5 ± 4.7 kg, height 1.75 ± 0.06 m, body fat 14.7 ± 2.6%) were randomly assigned to a control (normal training) group (Gc; n = 11) and an experimental group (Gex, n = 12) that also performed biweekly plyometric training. A force-velocity ergometer test determined PP. Characteristics of the squat jump (SJ) and the countermovement jump (CMJ) (jump height, maximal force and velocity before take-off, and average power) were determined by force platform. Video-camera kinematic analyses over a 40-m sprint yielded running velocities for the first step (VS), the first 5 m (V5m) and between 35 and 40 m (Vmax). Leg muscle volume was estimated using a standard anthropometric kit. Gex showed gains relative to controls in PP (p < 0.01); SJ (height p < 0.01; velocity p < 0.001), CMJ (height p < 0.001; velocity p < 0.001, average power p < 0.01) and all sprint velocities (p < 0.001 for V5m and Vmax, p < 0.01 for VS). There was also a significant increase (p < 0.05) in thigh muscle volume, but leg muscle volume and mean thigh cross-sectional area remain unchanged. We conclude that biweekly plyometric training of junior soccer players (including adapted hurdle and depth jumps) improved important components of athletic performance relative to standard in-season training. Accordingly, such exercises are highly recommended as part of an annual soccer training program.
authors.affiliation: Research Unit Evaluation and analysis of factors influencing sport performance, Higher Institute of Sport and Physical Education of Ksar Said, Tunis, Tunisia. csouhaiel@yahoo.fr
authors.forename: Mohamed Souhaiel
authors.initials: MS
authors.lastname: Chelly
authors.forename: Mohamed Ali
authors.initials: MA
authors.lastname: Ghenem
authors.forename: Khalil
authors.initials: K
authors.lastname: Abid
authors.forename: Souhail
authors.initials: S
authors.lastname: Hermassi
authors.forename: Zouhair
authors.initials: Z
authors.lastname: Tabka
authors.forename: Roy J
authors.initials: RJ
authors.lastname: Shephard
mesh_terms: D000293:Adolescent; D056352:Athletes; D054874:Athletic Performance / Q000502:physiology*; D006801:Humans; D007866:Leg / Q000502:physiology*; D008297:Male; D009119:Muscle Contraction / Q000502:physiology; D053580:Muscle Strength / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D012420:Running / Q000502:physiology*; D012916:Soccer / Q000502:physiology*; D013996:Time and Motion Studies; D055815:Young Adult