023: Predicting Injury: When Strength Alone is Not Enough

age injury strength training Aug 31, 2021

Muscular strength is the ability to exert force to overcome external resistance. Research has consistently shown that strength is central to normal function in activities of daily living and exercise (Ruiz et al., 2008), and it is inversely associated with all-cause mortality (Philips, 1986; Fujita et al., 1995; Laukkanen, Heikkinen, & Kauppinen, 1995). In short, the stronger you are, the longer you are likely to live and with fewer health complications.

Strength training is often recommended as an intervention for lowering the risk of musculotendinous injury, especially when the training programme aims to restore normal agonist-antagonist strength relationships (Fleck & Falkel, 1986; Lauersen, Andersen, & Anderson, 2018). Being strong in the positions required by your lifestyle or sporting activities makes sense because it facilitates the ability to resist external forces acting on the body that might otherwise push joints into precarious positions and threaten the integrity of the associated soft tissue structures.

Some coaches take this recommendation a step further by claiming that strength is the best predictor of injury. However, prospective data sets have enabled researchers to establish critical causal links between injury risk factors and primary injury occurrence. A notable finding from these studies is that strength alone does not predict primary injury, especially in the lower extremities (Hewitt et al., 2005; Zazulak et al., 2007).

Instead, a lack of proper neuromuscular control seems to be the most significant causal risk factor for predicting lower extremity injury, since it is abnormal neuromuscular control that leads to excessive trunk displacement (Zazulak et al., 2007) and altered knee mechanics during loading, which are the most prominent risk factors in individuals who experience subsequent ACL injury (Hewitt et al., 2005). Neuromuscular control is the ability of the nervous system to respond to afferent sensory information in a way that allows it to select the best efferent motor response according to the demands of the task and environment. Or, in simpler terms, it is the ability to activate the correct muscles in the appropriate sequence with the right amount of force in ways that best match the goal we are trying to accomplish.

Muscular strength is essential and will always remain so. It is an intrinsic factor that is associated with neuromuscular control. However, a consistent finding across many studies is that deficiencies in elements of neuromuscular control like poor balance and landing mechanics are the strongest predictors of injury (Boling et al., 2009; Gribble et al., 2016; Hewitt et al., 2005; McGuine et al., 2000; Padua et al., 2015; Zazulak et al., 2007). Thus, optimising neuromuscular control in the training programme is vital for preventing musculoskeletal injuries (Hubscher et al., 2010).

A combination of strength and neuromuscular control exercises specific to the individual's needs is critical if a person is to avoid recurrent injury and improve performance. Practising complex tasks in their entirety rather than in isolation is more efficient for skills transfer (Barnett et al., 1973). In terms of incorporating strength exercise, loading should begin from the inside out: use bodyweight only first before progressing to external resistance.

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References

Ruiz, J. R. et al. (2008) Association Between Muscular Strength and Mortality in Men: Prospective Cohort Study. British Medical Journal vol. 337, article 349.

Phillips, P. (1986) Grip Strength, Mental Performance, and Nutritional Status as Indicators of Mortality Among Female Geriatric Patients. Age & Ageing vol. 15, pp. 53-56.

Fujita, Y et al. (1995) Physical Strength Tests and Mortality Among Visitors to Health Promotion Centres in Japan.  Journal of Clinical Epidemiology vol. 48, pp. 1349-1359.

Laukkanen, P., Heikkinen, E., & Kauppinen, M. (1995) Muscle Strength and Mobility as Predictors of Survival in 75-84-Year-Old People. Age & Ageing vol. 24, pp. 468-473.

Laursen, J. B., Andersen, T. E., & Andersen, L. B. (2018) Strength Training as Superior, Dose-Dependent and Safe Prevention of Acute and Overuse Sports Injuries: A Systematic Review, Qualitative Analysis and Meta-Analysis. British Journal of Sports Medicine vol. 52, no. 24, pp. 1557-1563.

Fleck, S. J. & Falkel, J. E. (1986) Value of Resistance Training for the Reduction of Sports Injuries. Sports Medicine vol. 3, no. 1, pp. 61-68.

Hewitt, T. E. et al. (2005) Biomechanical Measures of Neuromuscular Control and Valgus Loading of the Knee Predict Anterior Cruciate Ligament Injury Risk in Female Athletes: A Prospective Study. American Journal of Sports Medicine vol. 33, pp. 492-501.

Zazulak, B.T. et al. (2007) Deficits in Neuromuscular Control of the Trunk Predict Knee Injury Risk: A Prospective Biomechanical-Epidemiological Study. American Journal of Sports Medicine vol. 35, pp. 1123-1130.

Boling, M.C. et al. (2009) A Prospective Investigation of Biomechanical Risk Factors for Patellofemoral Pain Syndrome: The Joint Undertaking to Monitor and Prevent ACL Injury (JUMP-ACL) Cohort. American Journal of Sports Medicine vol. 37, pp. 2108-2116.

Gribble, P. A. et al. (2016) Prediction of Lateral Ankle Sprains in Football Players Based on Clinical Tests and Body Mass Index. American Journal of Sports Medicine vol. 44, pp. 460-467.

McGuine, T. A. et al. (2000) Balance as a Predictor of Ankle Injuries in High School Basketball Players. Clinical Journal of Sports Medicine vol. 10, pp. 239-244.

Padua, D. A. et al. (2015) The Landing Error Scoring System as a Screening Tool for an Anterior Cruciate Ligament Injury Prevention Program in Elite Youth Soccer Athletes. Journal of Athletic Training vol. 50, pp. 589-595.

Hubscher, M. et al. (2010) Neuromuscular Training for Sports Injury Prevention: A Systematic Review. Medicine & Science in Sports & Exercise vol. 42, pp. 413-421.

Barnett, M. et al. (1973) Motor Skills Learning and the Specificity of Training Principle. Research Quarterly in Exercise & Sport vol. 44, pp. 440-447.