Strength imbalances and prevention of hamstring injury in professional soccer players: a prospective study.
Croisier, Jean-Louis ; ; et al
in American Journal of Sports Medicine (2008), 36(8), 1469-75
BACKGROUND: The relationship between muscle injury and strength disorders remains a matter of controversy. PURPOSE: Professional soccer players performed a preseason isokinetic testing aimed at ... [more ▼]
BACKGROUND: The relationship between muscle injury and strength disorders remains a matter of controversy. PURPOSE: Professional soccer players performed a preseason isokinetic testing aimed at determining whether (1) strength variables could be predictors of subsequent hamstring strain and (2) normalization of strength imbalances could reduce the incidence of hamstring injury. STUDY DESIGN: Cohort study (prognosis); Level of evidence, 1. METHODS: A standardized concentric and eccentric isokinetic assessment was used to identify soccer players with strength imbalances. Subjects were classified among 4 subsets according to the imbalance management content. Recording subsequent hamstring injuries allowed us to define injury frequencies and relative risks between groups. RESULTS: Of 687 players isokinetically tested in preseason, a complete follow-up was obtained in 462 players, for whom 35 hamstring injuries were recorded. The rate of muscle injury was significantly increased in subjects with untreated strength imbalances in comparison with players showing no imbalance in preseason (relative risk = 4.66; 95% confidence interval: 2.01-10.8). The risk of injury remained significantly higher in players with strength imbalances who had subsequent compensating training but no final isokinetic control test than in players without imbalances (relative risk = 2.89; 95% confidence interval: 1.00-8.32). Conversely, normalizing the isokinetic parameters reduced the risk factor for injury to that observed in players without imbalances (relative risk = 1.43; 95% confidence interval: 0.44-4.71). CONCLUSION: The outcomes showed that isokinetic intervention gives rise to the preseason detection of strength imbalances, a factor that increases the risk of hamstring injury. Restoring a normal strength profile decreases the muscle injury incidence. [less ▲]Detailed reference viewed: 210 (26 ULg)
Factors correlated with volleyball spike velocity.
Forthomme, Bénédicte ; Croisier, Jean-Louis ; et al
in American Journal of Sports Medicine (2005), 33(10), 1513-9
BACKGROUND: Spike effectiveness represents a determining element in volleyball. To compete at a high level, the player must, in particular, produce a spike characterized by a high ball velocity ... [more ▼]
BACKGROUND: Spike effectiveness represents a determining element in volleyball. To compete at a high level, the player must, in particular, produce a spike characterized by a high ball velocity. HYPOTHESIS: Some muscular and physical features could influence ball velocity during the volleyball spike. STUDY DESIGN: Descriptive laboratory study. METHODS: A total of 19 male volleyball players from the 2 highest Belgian national divisions underwent an isokinetic assessment of the dominant shoulder and elbow. Ball velocity performance (radar gun) during a spike test, morphological feature, and jump capacity (ergo jump) of the player were measured. We tested the relationship between the isokinetic parameters or physical features and field performances represented by spike velocity. We also compared first-division and second-division player data. RESULTS: Spike velocity correlated significantly with strength performance of the dominant shoulder (internal rotators) and of the dominant elbow (flexors and extensors) in the concentric mode. Negative correlations were established with the concentric external rotator on internal rotator ratio at 400 deg/s and with the mixed ratio (external rotator at 60 deg/s in the eccentric mode on internal rotator at 240 deg/s in the concentric mode). Positive correlations appeared with both the volleyball players' jump capacity and body mass index. First-division players differed from second-division players by higher ball velocity and increased jump capacity. CONCLUSION: Some specific strength and physical characteristics correlated significantly with spike performance in high-level volleyball practice. CLINICAL RELEVANCE: Our results could provide useful information for training management and propose some reflections on injury prevention. [less ▲]Detailed reference viewed: 316 (35 ULg)
Hamstring muscle strain recurrence and strength performance disorders
Croisier, Jean-Louis ; Forthomme, Bénédicte ; Namurois, Marie-Hélène et al
in American Journal of Sports Medicine (2002), 30(2, Mar-Apr), 199-203
We determined the frequency of strength disorders in 26 athletes with a history of hamstring muscle injury and recurrent strains and discomfort. We also assessed the effectiveness of rehabilitation to ... [more ▼]
We determined the frequency of strength disorders in 26 athletes with a history of hamstring muscle injury and recurrent strains and discomfort. We also assessed the effectiveness of rehabilitation to correct muscle performance. After concentric and eccentric isokinetic assessment, 18 athletes were found to have strength deficits, as determined by statistically selected cutoffs of peak torque, bilateral differences, and the flexors/quadriceps ratio. The discriminating character of the eccentric trial was demonstrated, combining a preferential eccentric peak torque deficit and a significant reduction of the mixed eccentric flexors/concentric quadriceps ratio. The athletes with muscle imbalances followed a rehabilitation program individually adapted from their strength profile. Treatment length was from 10 to 30 sessions and resulted in isokinetic parameter normalization in 17 of 18 subjects. Isokinetically corrected subjects were observed for 12 months after return to athletics. None sustained a clinically diagnosed hamstring muscle reinjury. Subjective intensity of pain and discomfort were significantly reduced, and they all returned to their prior level of competition. These results demonstrate that persistent muscle strength abnormalities may give rise to recurrent hamstring injuries and discomfort. An individualized rehabilitation program emphasizing eccentric training based on specific deficits contributes to a decrease in symptoms on return to sports. [less ▲]Detailed reference viewed: 107 (15 ULg)