DEFINING PERFORMANCE AFTER HAMSTRING STRAIN INJURY
– Written by Darren Paul, Qatar and Joao Brito, Portugal
"I was petrified of running into a channel. I just knew I was going to tear a muscle… the worst thing about it is that your instinct tells you to do what you have done all your life but you start thinking: oh no, don't…for six or seven years I hated it… I couldn't wait to retire… mentally I could do it, but physically I couldn't". This was Michael Owen’s recent admission of the impact the hamstring injuries that plagued a large part of his footballing career had on himself and the team1.
HAMSTRING IMPORTANCE AND PERFORMANCE
Coaches, players and supporters are for the most part, concerned with their team winning. The medical and sport science staff play an important role towards this objective by mitigating the risk of injury and enhancing performance. In doing this it is expected that the coach will have a squad ready and capable to perform on the field. Unfortunately, most teams will encounter players being lost through injury during crucial times of the season, for extended periods of time, and/or on repeated occasions. The outcome of this will likely have significant implications on morale, finances, and the team’s chances of success.
Hamstring strain injurie (HSI) remains common in team sports and one of the most challenging issues facing sports medicine practitioners2. In elite European football, the incidence of HSI has increased annually by 4% between 2001 and 20143 with high reinjury rates. The hamstrings play a significant role during important match winning actions such as sprinting past an opposing defender4. Accordingly, there is a growing body of research demonstrating measures of hamstring function, notably eccentric strength, as well as high speed running/sprinting exposure, as beneficial to performance5,6.
Although not impossible, a hamstring strain is unlikely to be a career ending injury. However, while an athlete should eventually be able to return to the field without any complications, there may be lingering morphological, physical, or psychological concerns which individually or collectively may negatively impact performance7. It is suggested that players may return to competition after hamstring injury having developed maladaptation’s that predispose them to subsequent injury8. In addition, following the initial trauma, players may worry about whether the muscle will fully return to its previous capacity, the potential effect on their physical ability, and the likely impact of being absent for any forthcoming important matches.
The force producing capabilities of the muscle have also shown to be altered during tasks such as running, which may further contribute to reinjury risk9. Players returning from an injury have shown to be moderately slower compared to uninjured players2, although this does improve over time. There is also evidence of a horizontal, but not vertical, force application deficit in the injured limb during running10. Such a scenario may resonate more with those ‘chronic rehabbers’ (i.e. players with persistent symptoms, or subsequent injuries of the same type and nature), particularly since the relevance of previous injury is perceived differently for injured than non-injured players11.
Following a HSI, changes may also occur in the connective tissue content of the scar tissue. This may include selective residual atrophy, damage to the intramuscular nerve branches at the site of injury, shifts in the knee flexor torque-joint angle relationship and associated neuromuscular activity deficits. These changes may induce potentially injurious kinematics8,12. For example, sagittal asymmetry in hip flexion, pelvic tilt, and medial rotation of the knee have also been reported following an injury, effectively altering certain movement patterns. The concern is that these may be moderating factors of future hamstring function.
Regaining hamstring function early and safely, while minimizing any detraining induced decline in physical performance, is an important part of the rehabilitation process. While there is no single intervention which optimally re-conditions the injured hamstring, performing strengthening exer-cises, notably the Nordic hamstring exercise and high-speed running, have gained support as being effective to mitigate injury risk as well as improving performance13,14.
Specifically, improvements in peak eccentric hamstring strength and force capacity, sprint and change of direction performance have also been found with the introduction of the Nordic hamstring exercise and/or high-speed running training5,15. Interestingly, the gains in change of direction performance were shown to be maintained despite an approximate 10% decrease in eccentric hamstring strength following a detraining period. This has led to inferences regarding several adaptations that may occur in response to training, such as: increased fascicle length16 and/or enhanced neuromuscular parameters15. Practically, this indicates that performance improvements may still be maintained even when the Nordic hamstring exercise is removed or reduced during specific periods, such as the winter break and congested match schedules. These findings are valuable to aid practitioners in their programming.
The implementation of hamstring strengthening exercises is likely to differ between sports teams and clubs, based on a myriad of factors such as match schedules, player and coach perceptions; and education around such interventions. Accordingly, teams may adopt a different model of training that represents an experience-based approach. This approach might not resemble general recommendation, but conforms with these circumstances. For example, performing the Nordic hamstring exercise before training attenuated sprint performance declines but decreased eccentric hamstring peak torque during football-specific exercise17. More recently, Lovell and colleagues18 showed biceps femoris fascicle length increases were more likely to increase when performing the Nordic hamstring exercise before, compared to after, training. However, increases in biceps femoris muscle thickness and pennation angle were found when Nordics were performed after, compared to before, training. As inadequate eccentric strength and fatigue are both risk factors for HSI, strength training should be considered along with the development of peak eccentric strength, as a component of programmes aimed at reducing injury risk in multiple-sprint sports19. Such findings demonstrate there may be benefits to performing these exercises both before and after a training session, perhaps reducing the negative influence of fatigue.
RETURN TO SPORT PERFORMANCE
The return to sport (RTS) criteria are suggested to represent a key component of the rehabilitation process. It is considered a vital part in order to fully address and prepare the player. Recently, van der Horst and colleagues20 published an expert consensus on the RTS after HSI. Consensus (defined as agreement of >70%) was only reached for repeated sprint ability, single leg bridge, deceleration drills and position specific global positioning system targeted match specific rehabilitation, highlighting the disparity in approaches. The RTS decision-making process is based on the evaluation of the relevant health (medical and injury-specific factors) and activity (performance factors) risks, but is also influenced by contextual factors known as decision modifiers (e.g., timing of the season, competitive level, coach and /or stakeholder pressure)21. Considering the multidimensional nature of HSI, the return to sport criteria should not be validated as univariate factors, but interaction of context dependent criteria that also includes different weighting.
It is believed that a criteria-based rather than a time-based approach will objectify all physical variables involved in the return to sport, allowing for a decision to be less subjective or experience dependent. While a returning athlete may achieve the specified performance outcomes, there may still be gaps within the rehabilitation programme that may not fully prepare them to perform on the field. Blanch and Gabbett22 noted that most protocols for ascertaining RTS clearance focused on healing status and functional tests, with little information pertaining to the completion of an appropriate volume of training. This is consistent with some potential concerns of a mismatch between what is currently performed in training and what is expected in match play.
Targeting a set performance criterion (e.g. time to complete a sprint test) may offer an appealing framework; however, judging an athlete’s capacity solely on some isolated measures of performance has its limitations.
There is a level of acceptance that an athlete may return to the competition even though they may not have fully completed the final stages of the rehabilitation process. However, simply returning to the field does not mean that the player can achieve optimal performance, as there is a significant distinction between fit to play and fit to perform.
Deficits in eccentric and concentric strength and strength ratios have been shown to persist beyond the return to sport process23. Worryingly, the ability to perform repeated sprints may also be impaired as long as two years after returning to competition24 while greater reductions in isokinetic knee flexor torque and the concentric hamstring: quadriceps peak torque ratio have been observed after repeated-sprint running only in the injured (kicking) leg, and only in the previously injured subjects25. Such findings are insightful to the long-term care and management of players, even after returning to competition.
Sport teams are investing heavily into staff, facilities, and equipment to better their understanding and advance current practice of athlete care and performance. Daily subjective and objective measures, monitoring training and match activity, as well as calculating workloads, seem to be daily duties within sports science and medicine teams. Commonly, teams do some form of benchmarking, identifying ‘red flags’, and comparing pre- and post-injury data to aid the decision-making during the rehabilitation process. While such data may offer a reference point, it should also be interpreted with a sense of caution when considering a player’s return. Classifying a post-injury drop in match workload (e.g. sprints), compared to pre-injury data, as being solely a physical limitation is a reductionist viewpoint, and ignores the context and complexity of sports performance.
A reluctance to sprint may be attributed to several factors, including a general fear of reinjury (psychological reservations), or conserving oneself for selection of the national team (environmental contextual factors). It may even be a player’s (non)subliminal action of pacing themselves, constituting part of a self-determined final phase of their rehabilitation. Indeed, it would seem intuitive for some players to ‘ease their way back’ into the competitive environment. A player taking this approach may be cognizant of their injury history, playing age and/or experience; it may even have been recommended by a teammate whom has previously had a similar injury. Such context specific details cannot be captured solely from the physical workloads presented from time and motion analyses. Nonetheless, if the returning player produces a significant action (scoring a goal) or match winning performance, the relatively low match workloads may simply be a distant secondary consideration for the coach!
HSI carries a high burden and sub-stantial financial implications26,27. For the professional player, an average of 18 days and three matches are missed per season, and cumulatively, this equates to a club average of 15 matches and 90 days missed per season28. The inability to play and prolonged absence from play during rehabilitation affects both the individual player and the team. Losing the star player can have an impact on winning impor-tant games/competitions, marketing, and even ticket sales, which may produce an unwanted burden to the finances of a club. While this is relevant to any injury, the high frequency of reinjury suggests this may be particularly pertinent to HSI.
It is well established that player availability is highly important for success29. However, even when a player has returned to the team following a HSI, the coach’s opinion of player performance appears to be lower than pre-injury. Statistics show that staff (coaches, medical) and a large percentage of players (67%), believe a lower limb injury to have a negative impact on team performance30. This also suggests that some players may return to sport prior to complete resolution of the injury and in a suboptimal state31. If this occurs, consider the effect it may have on the coach and the player’s teammates. The difficulty is establishing whether this is a normal part of the RTS process, or whether it is indicative of some shortfalls in the player’s physical preparation and overall rehabilitation process. If it is communicated to the coach that they are unlikely to be receiving back the same player (in terms of performance) that was in the team prior to the injury, it then may impact upon the coach’s selection process. However, coaches may be willing to take the risk, and should clearly be made aware of the potential impact on team performance, and the increased risk of reinjury. Since team sports can be multimillion-dollar industries, and the difference between winning and losing games hold enormous financial impact, coaches need to be mindful that certain decisions regarding players can prove very costly.
There are many challenges to losing a player - possibly a repositioning of players in the team, a different playing style or selecting a substitute player who has had very little game time over recent weeks or months. However, following the loss of influential team members, the support staff have an important role in providing a strategy that will not adversely impact on the team. Rather than seeing the situation as a threat to success, players should be encouraged to see the situation as a challenge they are capable of overcoming.
HSI can impact muscle morphology, an athlete’s capacity to perform optimally, and the team’s chances of success, which may not go unnoticed by the coach and support staff. Establishing reference points may be useful but should not be the sole focus of a rehabilitation process, rather a holistic approach should be the objective. Appropriate strategies such as strengthening exercises and performing sprinting activities as part of training should provide some reinjury protection as well as increasing functional performance. The coach should be informed when it is suspected that RTS may impact performance, particularly during the earlier stages of rehabilitation. It is important that the process of returning to performance is a shared decision making and that the player plays a significant role throughout the process.
Darren Paul M.Sc.
Exercise Sport Science Department,
Aspetar Orthopaedic and Sports Medicine Hospital
Joao Brito Ph.D.
Performance and health unit,
Portuguese Football Association,
Mendiguchia J, Alentorn-Geli E, Brughelli M. Hamstring strain injuries: are we heading in the right direction? Br J Sports Med 2012;46:81-5.
Ekstrand J, Waldén M, Hägglund M. Hamstring injuries have increased by 4% annually in men's professional football, since 2001: a 13-year longitudinal analysis of the UEFA Elite Club injury study. Br J Sports Med 2016; bjsports–2015–095359–9. http://doi.org/10.1136/bjsports-2015-095359
Morin JB, Gimenez P, Edouard P. Sprint acceleration mechanics: the major role of hamstrings in horizontal force production. Front Physiol. 2015; 24:6:404.
Ishøi L, Hölmich P, Aagaard P, et al. Effects of the Nordic hamstring exercise on sprint capacity in male football players: a randomized controlled trial. J Sports Sci. 2018; 36(14):1663-1672. http://doi.org/10.1080/02640414.2017.1409609
Mendiguchia J, Martinez-Ruiz E, Morin JB, Samozino P, Edouard P, Alcaraz PE, Esparza-Ros F, Mendez-Villanueva A. Effects of hamstring‐emphasized neuromuscular training on strength and sprinting mechanics in football players. 2015; 25(6):e621-9.
Timmins RG. Architectural adaptations of muscle to training and injury: a narrative review outlining the contributions by fascicle length, pennation angle and muscle thickness. Br J Sports Med. 2016; 50: 1467-1472.
Fyfe J, Opar D, Williams M, Shield A. The role of neuromuscular inhibition in hamstring strain injury recurrence. J Electromyogr Kinesiol. 2013; 23(3): 523-30.
Timmins RG, Bourne MN, Shield AJ et al. Short biceps femoris fascicles and eccentric knee flexor weakness increase the risk of hamstring injury in elite football (soccer): a prospective cohort study. Br J Sports Med. 2015; 50(24):1524-1535.
Brughelli M, Cronin J, Mendiguchia J, et al. Contralateral leg deficits in kinetic and kinematic variables during running in Australian rules football players with previous hamstring injuries. J Strength Cond Res. 2010;24(9):2539-44. doi: 10.1519/JSC.0b013e3181b603ef.
Zech A, and Wellmann K. Perceptions of football players regarding injury risk factors and prevention strategies. PLoS ONE. 2017; 12(5): e0176829–11. http://doi.org/10.1371/journal.pone.0176829
Silder A, Heiderscheit BC, Thelen DG, et al. MR observations of long-term musculotendon remodelling following a hamstring strain injury. Skeletal Radiol. 2008;37(12):1101-9
Petersen J, Thorborg K, Nielsen MB et al. 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.
Bourne MN, Timmins RG, Opar DA. An evidence-based framework for strengthening exercises to prevent hamstring injury. Sports Med. 2018;48(2):251-267. doi: 10.1007/s40279-017-0796-x
Delahunt E, McGroarty M, Nordic hamstring exercise training alters knee kinematics and hamstring activation patterns in young men. Eur J Appl Physiol. 2016; 116(4): 663-72.
Alonso Fernandez D, Docampo-Blanco P, Martinez-Fernndez J, Changes in muscle archiecture of biceps femoris induced by eccentric strenght training with nordic hamstring exercise. Scan J Med sci Sports. 2018; 28(1): 88-94.
Lovell R, Siegler JC, Knox M, Brennan S, Marshall P. Acute neuromuscular and performance responses to Nordic hamstring exercises completed before or after football training. J Sports Sci. 2016; 34(24): 2286-2294.
Lovell R, Knox M, Weston M, et al. Hamstring injury prevention in soccer: Before or after training? Scand J Med Sci Sports. 2018; 28(2):658-666. doi: 10.1111/sms.12925. Epub 2017 Jun 28.
Delextrat A, Piquet J, Matthews MJ, & Cohen, D. Strength-endurance training reduces the hamstrings strength decline following simulated football competition in female players. Front Physiol. 2018; 9: 687–12. http://doi.org/10.3389/fphys.2018.01059
van der Horst N, Backx F, Goedhrt EA, Huisstede BM, HIPS Delphi Group. Return to play after hamstring injuries in football (soccer): a worlwide Delphi procedure regarding definition, medical criteria and decision making. Br J Sports Med. 2017; 51(22): 1583-1591.
Arden CL, Bizzini M, Bahr R. Is it time for consensus on return to play after injury: five key questions. Br J Sports Med. 2015; 0:0.
Blanch P, Gabbett t. Has the athlete trained enough to return to play safely? The acute: chronic workload ratio permits clinicians to quantify a players risk of subsequent injury. Br J Sports Med. 2016; 50(8):471-5.
Maniar N, Shield AJ, Williams MD, et al. Hamstring strength and flexibility after hamstring strain injury: a systematic review and meta-analysis. Br J Sports Med. 2016; 50(15): 909–920. http://doi.org/10.1136/bjsports-2015-095311
Røksund O, Kristoffersen M, Bogen B, et al. Higher drop in speed during a repeated sprint test in soccer players reporting former hamstring strain injury. Front Physiol. 2017; 8(Pt 8): 1369–8. http://doi.org/10.3389/fphys.2017.00025
Lord C, Blazevich AJ, Drinkwater EJ, Ma’ayah, F. Greater loss of horizontal force after a repeated-sprint test in footballers with a previous hamstring injury. J Sc Med Sport. 2019; 22(1): 16-21. http://doi.org/10.1016/j.jsams.2018.06.008
Hickey J, Shield AJ, Williams MD, et al. The financial cost of hamstring strain injuries in the Australian Football League. Br J Sports Med. 2014;48(8):729–30.
Bahr R, Clarsen B, Ekstrand J. Why we should focus on the burden of injuries and illneses, not just their incidence. Br J Sports Med, 2018. 52; (16): 1018-1021.
Woods C, Hawkins RD , Maltby S , et al Football association medical research programme. the football association medical research programme: an audit of injuries in professional football--analysis of hamstring injuries. Br J Sports Med 2004; 38:36–41
Ekstrand J, Lundqvist D, Lagerback L, et al. Is there a correlation between coaches’ leadership styles and injuries in elite football teams? A study of 36 elite teams in 17 countries. Br J Sports Med. 2018; 52(8): 527-531.
O Brien J, Finch C. Injury prevention exercise programmes in professional youth soccer: understanding the perceptions of programme deliverers. BMC Open Sport Exerc Med. 2016; doi:10.1136/bmjsem-2015-000075
Verrall G, Kalairajah Y, Slavotinek J, Spriggins A. Assessment of palyer performance following return to sport after hamstring muscle strain injury. J Sci Med Sport. 2006; 9(1-2): 87-90.
Horst N, Hoef S, Reurink G. Return to play after hamstring injuries: a qualitative systematic review of definitions and criteria. Sports Med 2016; 46(6): 899–912. http://doi.org/10.1007/s40279-015-0468-7
Ivarsson A, Tranaeus U, Johnson U, Stenling A. Negative psychological responses of injury and rehabilitation adherence effects on return to play in competitive players: a systematic review and meta-analysis. Open Access Journal of Sports Medicine. 2017; 8: 27–32. http://doi.org/10.2147/OAJSM.S112688
Slider A, Thelen DG, Heiderscheit BC. Effects of prior hamstring strain injury on strength flexibility and running mechanics. Skeletal Radiol. 2010;37(12):1101-9. doi: 10.1007/s00256-008-0546-0. Epub 2008 Jul 23.
Sole G, Milosavljevic S, Nicholson H, Sullivan S. Altered muscle activation following hamstring injuries. Br J Sports Med. 2012; 46(2): 118–123. http://doi.org/10.1136/bjsm.2010.079343
Tol JL, Hamilton B, Eirale C, et al. At return to play following hamstring injury the majority of professional football players have residual isokinetic deficits. Br J Sports Med. 2014; 48(18): 1364–1369. http://doi.org/10.1136/bjsports-2013-093016.
Targeted Topic – Hamstring Injuries - Aspetar Experience
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