The Effects of Injury Preventive Warm-Up Programs on Knee Strength Ratio in Young Male Professional Soccer Players

Abstract

PurposeWe aimed to investigate the effect of FIFA 11+ (11+) and HarmoKnee injury preventive warm-up programs on conventional strength ratio (CSR), dynamic control ratio (DCR) and fast/slow speed ratio (FSR) in young male professional soccer players. These ratios are related to the risk of injury to the knee in soccer players.MethodsThirty-six players were divided into 3 groups; FIFA 11+, HarmoKnee and control (n = 12 per group). These exercises were performed 3 times per week for 2 months (24 sessions). The CSR, DCR and FSR were measured before and after the intervention.ResultsAfter training, the CSR and DCR of knee muscles in both groups were found to be lower than the published normal values (0.61, 0.72, and 0.78 during 60°.s−1, 180°.s−1 and 300°.s−1, respectively). The CSR (60°.s−1) increased by 8% and FSR in the quadriceps of the non-dominant leg by 8% in the 11+. Meanwhile, the DCR in the dominant and non-dominant legs were reduced by 40% and 30% respectively in the 11+. The CSR (60°.s−1) in the non-dominant leg showed significant differences between the 11+, HarmoKnee and control groups (p = 0.02). As for the DCR analysis between groups, there were significant differences in the non-dominant leg between both programs with the control group (p = 0.04). For FSR no significant changes were found between groups.ConclusionsIt can be concluded that the 11+ improved CSR and FSR, but the HarmoKnee program did not demonstrate improvement. We suggest adding more training elements to the HarmoKnee program that aimed to enhance hamstring strength (CSR, DCR and FSR). Professional soccer players have higher predisposition of getting knee injuries because hamstring to quadriceps ratio were found to be lower than the average values. It seems that the 11+ have potentials to improve CSR and FSR as well as prevent knee injuries in soccer players.

Effect of Different Core Exercises Applied During the Season on Strength and Technical Skills of Young Footballers

“…In studies investigating the correlation between core exercises and sporting performance, sportspeople with core training were not identified to have positive development in sporting performance (Stanton et al 2004, Tse et al 2005, Nesser et al 2008). Contrary to this, there are research results reporting that adding core training to football training significantly developed strength and power (Brito et al 2010, Daneshjoo et al 2012. The causes of these differences in study results may be that studies were applied in different branches like swimming, rowing, and football and that branch-specific techniques may affect power production during movement.…”

Knee Isokinetic Torque Imbalance in Female Futsal Players

“…The way this ratio was calculated in the present study provides important information about knee flexor/extensor imbalance along the entire joint range of motion in female futsal players, and might allow for the identification of possible injury risks during this range of motion. The HQ ratio is frequently used as an index to evaluate the stabilizing efficiency of the knee joint muscles [9][10][11] . In this study, HQ ratios varied throughout the joint range of motion, with lower values at 30° to 45° of knee flexion, and higher values at 65° to 80°.…”

“…The hamstrings/quadriceps peak torque ratio (HQ ratio) is an index used to evaluate the stabilizing efficiency of the knee joint muscles 9,10 . Specifically, it measures the ability of the hamstrings to neutralize tibial anterior translational forces produced by the knee extensors, providing dynamic joint stability during knee extension [9][10][11] . It is well established that the HQ physiological peak torque ratio is 60% on average, representing the level of muscular balance.…”

The effectiveness of different exercises protocols to prevent the incidence of hamstring injury in athletes

“…In order to simulate the situation where hamstring strain occurs, athletes were instructed to forward incline the trunk when sprinting. Conversely, Daneshjoo et al 27 observed no effect of two typically recommended specific injury prevention programmes (FIFA 11 + and Harmo Knee) to enhance hamstring strength in professional football players. More recently, Naclerio et al 24 reported that four weeks (12 sessions) of an injury prevention programme comprising three sets of eight repetitions of the Nordic curl, forward lunges on a Bosu ® , balance trainer and eccentric single-leg dead lifts was effective in improving the maximal isometric force at both closed (80°) and open (35°) knee angles.…”

“…In addition, to the active lengthening observed during sprints or kicking, the hamstring acts as knee stabilisers counteracting and balancing the actions of the quadriceps during sportspecific activities, such as landing, deceleration or change of direction. Therefore, specific drills involving, repeated sprints, jumps, hops combined with unstable coreexercises, namely one-leg squat or lunges unstable surfaces have been proposed as effective methods for preventing hamstring injuries 24,27,28 . Verral et al 28 reported a significant reduction of hamstring injuries in Australian football players after a four-year high-intensity intervaltraining programme combined with passive isometric hamstring stretching.…”