Recovery kinetics of knee flexor and extensor strength after a football match.

Dimitrios Draganidis,Vassilios Gourgoulis,Alexandra Avloniti,Athanasios Chatzinikolaou,Asimenia Gioftsidou,Yiannis Koutedakis,Konstantinos Margonis,Ioannis G Fatouros,Andreas D Fouris,Chariklia K Deli,José C Barbero-Álvarez,Ioannis I Douroudos,Paraskevi Malliou,Magni Mohr,Athanasios Z Jamurtas

doi:10.1371/journal.pone.0128072

Abstract

We examined the temporal changes of isokinetic strength performance of knee flexor (KF) and extensor (KE) strength after a football match. Players were randomly assigned to a control (N = 14, participated only in measurements and practices) or an experimental group (N = 20, participated also in a football match). Participants trained daily during the two days after the match. Match and training overload was monitored with GPS devices. Venous blood was sampled and muscle damage was assessed pre-match, post-match and at 12h, 36h and 60h post-match. Isometric strength as well as eccentric and concentric peak torque of knee flexors and extensors in both limbs (dominant and non-dominant) were measured on an isokinetic dynamometer at baseline and at 12h, 36h and 60h after the match. Functional (KFecc/KEcon) and conventional (KFcon/KEcon) ratios were then calculated. Only eccentric peak torque of knee flexors declined at 60h after the match in the control group. In the experimental group: a) isometric strength of knee extensors and knee flexors declined (P<0.05) at 12h (both limbs) and 36h (dominant limb only), b) eccentric and concentric peak torque of knee extensors and flexors declined (P<0.05) in both limbs for 36h at 60°/s and for 60h at 180°/s with eccentric peak torque of knee flexors demonstrating a greater (P<0.05) reduction than concentric peak torque, c) strength deterioration was greater (P<0.05) at 180°/s and in dominant limb, d) the functional ratio was more sensitive to match-induced fatigue demonstrating a more prolonged decline. Discriminant and regression analysis revealed that strength deterioration and recovery may be related to the amount of eccentric actions performed during the match and athletes' football-specific conditioning. Our data suggest that recovery kinetics of knee flexor and extensor strength after a football match demonstrate strength, limb and velocity specificity and may depend on match physical overload and players' physical conditioning level.

Highlights

During Association football competition, football players cover a distance of 9–13 km at high intensity including >200 high-intensity runs that require demanding changes in direction [1] with forceful accelerations/decelerations [2] causing fatigue during and at the end of a game [3]
Our initial null research hypotheses state that: i) strength performance fluctuations of knee extensors (KE) and KF following a football game will be related to knee velocity, ii) the conventional and the functional ratios will respond differently to a football game, iii) dominant and non-dominant limbs will demonstrate a different response pattern of KE and KF responses, iv) KE and KF strength decline and recovery following a football game will be associated with players' conditioning status and v) the rate of strength recovery of KF and KE after the game will be related to high-intensity activities performed by the players during the game
Limited information exists regarding the independent effects of football practice on strength performance responses

Summary

Introduction

During Association football (soccer) competition, football players cover a distance of 9–13 km at high intensity including >200 high-intensity runs that require demanding changes in direction [1] with forceful accelerations/decelerations [2] causing fatigue during and at the end of a game [3]. The occurrence of acceleration/deceleration motions during running, sprinting, tackling, turning, changing pace, physical contact with opposition, jumping and changes in direction have been associated with muscle damage induced by football matches and their frequency may affect post-match recovery kinetics [6, 16] These activities incorporate a strong eccentric component which is associated with the onset of muscle damage [17] eliciting muscular pain, acute inflammatory response and performance deterioration for as long as 1–5 days after a match [18, 19]. Match-induced fatigue on changes in KF and KE strength performance at slow vs fast contraction velocities, ii) investigate whether the conventional or the functional ratio is more affected by a football game, iii) determine whether KF and KE strength performance fluctuations demonstrate a different response pattern in dominant vs non-dominant limb, iv) determine factors that may affect strength decline during the inflammatory phase after a football game and v) determine factors that may affect kinetics of strength recovery during the recovery phase of the post-game period. Our initial null research hypotheses state that: i) strength performance fluctuations of KE and KF following a football game will be related to knee velocity, ii) the conventional and the functional ratios will respond differently to a football game, iii) dominant and non-dominant limbs will demonstrate a different response pattern of KE and KF responses, iv) KE and KF strength decline and recovery following a football game will be associated with players' conditioning status and v) the rate of strength recovery of KF and KE after the game will be related to high-intensity activities performed by the players during the game

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