Preventive Effects of Eccentric Training on Acute Hamstring Muscle Injury in Professional Baseball

Abstract

Background:Hamstring injuries are the second most common injury causing missed days in professional baseball field players. Recent studies have shown the preventive benefit of eccentric conditioning on the hamstring muscle group in injury prevention. Specifically, Nordic-type exercises have been shown to decrease the incidence of acute hamstring injuries in professional athletes.Purpose:This was a prospective study performed in coordination with a single Major League Baseball (MLB) organization (major and minor league teams) that targeted the effects of Nordic exercises on the incidence of acute hamstring injuries in the professional-level baseball player.Study Design:Prospective cohort study; Level of evidence, 2.Methods:The daily workouts of 283 professional baseball players throughout all levels of a single MLB organization were prospectively recorded. The intervention group participated in the Nordic exercise program and was compared with a randomly selected control group of professional athletes within the organization not participating in the exercise program. The incidence of hamstring injuries in both groups was compared, and the total number of days missed due to injury was compared with the 2 previous seasons.Results:There were 10 hamstring injuries that occurred during the 2012 season among the 283 professional athletes that required removal from play. There were no injuries that occurred in the intervention group (n = 65, 0.00%; P = .0381). The number needed to treat (NNT) to prevent 1 hamstring injury was 11.3. The average repetitions per week of the injured group were assessed at multiple time points (2, 4, 6, and total weeks) prior to injury. There were significantly fewer repetitions per week performed in the injured group at all time points compared with overall average repetitions per week in the noninjured group (P = .0459, .0127, .0164, and .0299, respectively). After beginning the Nordic exercise program, there were 136 total days missed due to a hamstring injury during the 2012 season. This number was less than the 2011 season (273 days missed) and the 2010 season (309 days missed).Conclusion:Study results indicate the initiation of Nordic hamstring exercises may decrease the incidence of acute hamstring injuries and potentially decrease the total number of days missed due to injury in professional baseball players.Clinical Relevance:The financial and competitive interest in professional baseball players is of large importance to the player, team, and fans. Prevention of injuries is as important to all parties involved as the treatment and rehabilitation following an injury. This prospective study shows the initiation of a simple, free exercise can reduce the incidence of hamstring injury in the professional-level baseball player.

Stretch imposed on active muscle elicits positive adaptations in strain risk factors and exercise‐induced muscle damage

“…Substantially greater increases in ROM, elastic energy storage and stretch tolerance have recently been reported following active muscle stretching 23 when compared to passive stretch practices. 24,28 Furthermore, substantial reductions in both new and recurrent muscle strain injuries have been reported following isotonic eccentric training routines, [16][17][18] using similar loading strategies to the present study. Collectively, these findings indicate that stretching of a muscle while in a fully contracted state is substantively more effective than current passive static stretching practices for achieving clinically relevant changes in passive mechanical properties commonly associated with muscle strain injury.…”

“…The concomitant and substantial adaptations in multiple functional, physiological, and mechanical characteristics highlight the likely adaptations following eccentric training routines that may enhance our understanding of the previously reported reductions in muscle damage and both new and recurrent muscle strain injuries following these training routines. The potential for significant practical outcomes exists as training similar to that used in the present study can be applied within the clinical rehabilitative environment using isokinetic training practices or in applied athletic environments by the use of partner‐assisted stretches imposed with the muscles in a highly‐active state.…”

“…The superior adaptive potential of high-loading isotonic eccentric training (compared with isometric or concentric training) has been demonstrated repeatedly, with greater increases in muscle mass, 11 strength, 12 fascicle length, 13 and protection against EIMD 14,15 being reported. Furthermore, substantial reductions in new and recurrent muscle strain injury incidence have been reported following the completion of isotonic eccentric training programs, [16][17][18] with a threefold increase in the likelihood of injury when eccentric training is not performed. 19 Collectively, these data are indicative that greater tissue loading, evident from intense eccentric contractions (ie, stretch imposed on highly-active muscle), likely induces wide-ranging adaptations in mechanical and physiological properties that attenuates EIMD and provides a greater protective effect than passive static muscle stretching.…”

Isokinetic Performance of Knee Flexor and Extensor Muscles in American Football Players from Brazil

“…The high number of athletes below the recommended standards for conventional and functional ratios suggests that efforts must to be made for balancing the torque production capacity of the knee flexor and extensor muscles and help to prevent future injuries. Petersen et al 25 and Seagrave III et al 26 have implemented training programs to restore muscle balance between the anterior and posterior thigh muscles on soccer and baseball players, respectively. Their training protocols involving the Nordic hamstring exercise have been proven effective in preventing primary and recurrent hamstring injuries 25 , as well as in reducing the total number of days missed due to injury 26 .…”

Effects of 7-Week Shoulder Exercise Intervention on Joint Mobility, Strength and Function in Diabetics and Non-Diabetics

“…54 Similarly, the average improvement in SPADI was 9.7, which is below the MDC for SPADI reported in the literature (13.2-23.1). [54][55][56] While this observation may suggest that the intervention effects were too small to be clinically meaningful, taking into account that the participants did not have clinical shoulder pain at baseline, adds meaning to the relatively small improvements.…”