A healthy team is a happy team – and financially stable. That is to say, athletes don’t want to be missing days on the field or put on the disabled list because of an injury. An injured player not only costs the team money, but also the player. The second leading cause for being placed on the disabled list for field position players is hamstring injuries (6, 9). They are also the fourth leading cause for all players (6, 9). A 2004 study stated during the late-swing phase of the gait cycle, the hamstring muscle group is maximally loaded and lengthened (7), as well as, at greatest risk for injury (9). Hamstring injuries can happen when the hamstring muscles are not properly warmed up or are fatigued, or when there is a sudden need for speed. Sprinting has a significantly higher force requirement compared to walking (2, 8, 9). When a baseball player suddenly takes off for a base, there is potential for hamstring injury.
Training and exercising the muscles can help strengthen the muscle group. Eccentric conditioning is meant to help strengthen the muscle group and therefore, reduce the risk for injury. Eccentric muscle exercises are defined as active lengthening of muscle fibers while contracting (9). For example, when you lower your arms during a bicep curl this action is considered “eccentric”. Nordic exercise is a great example for eccentric strength (4). Nordic exercises begin with the athlete on their knees and ankles secured by either specialized equipment or a partner. The athlete then resists forward-falling as long as possible, slowly lowering themselves to a position parallel to the floor (9). This action eccentrically engages the hamstring muscles. The athlete then allows themselves to fall, catching themselves with their hands and quickly pushing themselves back up to the starting position (9). Nordic hamstring exercises have been proven to reduce hamstring injuries in all levels of soccer players (5) and professional rugby players (3, 6). One study decided to test the theory on all levels of baseball players (major and minor leagues).
Let’s take a look at Their Science:
A 2014 study assessed 99 baseball players from all levels of competition in a single MLB organization during a single season. A single season included 162 games and all spring training activities prior to the season. Players were divided into an intervention group (n=65), which included Nordic exercises during training, and a control group (n=34) which did not participate in Nordic exercises. Players participating in the intervention group were required to perform 3.5< repetitions per week. Hamstring injuries were considered any injury to the hamstring muscle group which cause a player to be removed from the line-up for at least one day. All injuries meeting the designated criteria were recorded. (9)
So, what did they find?
The study found the intervention group experienced significantly less hamstring injuries compared to the control group. If you take a look at Table 1 below, you can see that the control group experienced 3 injuries, while the intervention group had none. In Table 2, you can see 136 total days were missed due to hamstring injury in the 2012 season. While in the 2011 and 2010 season, 273 and 309 days were missed, respectively. (9)
So, what does this mean?
This study suggests intervention with Nordic exercise can significantly reduce the risk of hamstring injuries in baseball players. Other studies have shown similar conclusions with soccer and rugby players (3, 5, 6). Repeat bouts of eccentric muscle training, such as Nordic exercises, are documented to produce a beneficial adaptation in the length-tension curve of the muscle by recruiting more sacromeres, resulting a stronger contraction at longer muscle lengths – providing for less injury prone contractions (1, 9). Meaning, eccentric training increases eccentric strength (4).
While the results from this study coincide with other research, not every sport has been evaluated on a scientific level. Therefore, it is important to keep in mind what kind of player you are. This study managed to maintain well documented records and keep track of training interventions. However, aside from the Nordic exercise, other training carried out by the players was not shared or evaluated in publication. Other training techniques may contribute to strengthening hamstring muscles. While adding Nordic exercise appears to have a beneficial impact, athletes should not negate other strategies to improving their muscle strength. There are lots of techniques and tools available to help athletes improve and monitor their body. It is vital athletes consider how they are training their body and where there may be potential for injury. Knowing where there is risk, allows athletes to focus on adapting their training regime in order to move their body to a state of lower risk. So, think about your sport, consider your lifestyle and evaluate your training. Make sure you athletic career progresses and your training is well-rounded.
Thank you for reading! I hope you feel more informed. If you have any questions or comments, please feel free to leave a shout out!
- Brockett CL, Morgan DL, Proske U. Human hamstring muscles adapt to eccentric exercise by changing optimum length. Med Sci Sports Exerc. 2001;33:783-790.
- Chumanov ES, Heiderscheit BC, Thelen DG. The effect of speed and influence of individual muscles on hamstring mechanics during the swing phase of sprinting. J Biomech. 2007;40:3555-3562
- Gabbe BJ, Branson R, Bennell KL. A pilot randomised controlled trial of eccentric exercise to prevent hamstring injuries in community-level Australian Football. J Sci Med Sport. 2006;9:103-109.
- Mjølsnes R, Arnason A, Osthagen T, Raastad T, Bahr R. A 10-week randomized trial comparing eccentric vs. concentric hamstring strength training in well-trained soccer players. Scand J Med Sci Sports. 2004;14:311-317.
- Petersen J, Thorborg K, Nielsen MB, Budtz-Jorgensen E, Holmich P. Preventive effect of eccentric training on acute hamstring injuries in men’s soccer: a cluster-randomized controlled trial. Am J Sports Med. 2011;39:2296-2303.
- Posner M, Cameron KL, Wolf JM, Belmont PJ Jr, Owens BD. Epidemiology of Major League Baseball injuries. Am J Sports Med. 2011; 39:1676-1680.
- Proske U, Morgan DL, Brockett CL, Percival P. Identifying athletes at risk of hamstring strains and how to protect them. Clin Exp Pharmacol Physiol. 2004;31:546-550.
- Schache AG, Wrigley TV, Baker R, Pandy MG. Biomechanical response to hamstring muscle strain injury. Gait Posture. 2009;29:332-338.
- Seagrave III, R. A., Perez, L., McQueeney, S., Toby, E. B., Key, V., & Nelson, J. D. (2014). Preventive effects of eccentric training on acute hamstring muscle injury in professional baseball. Orthopaedic journal of sports medicine, 2(6), 2325967114535351.