A Novel Device Using the Nordic Hamstring Exercise to Assess Eccentric Knee Flexor Strength: A Reliability and Retrospective Injury Study

Abstract

Hamstring strain injury (HSI) is the most common injury type in a number of sports 4,9,17 and is notorious for its high recurrence rate. A high proportion of HSIs are thought to occur during the terminal swing phase of high-speed running, 5 when the hamstrings are required to perform a forceful eccentric contraction. 20,23 Lower eccentric knee flexor strength has been reported as a risk factor for future HSI,8,19 indicating the importance of eccentric strength for HSI avoidance. 3,18 Further, previously strained hamstrings display reduced levels of eccentric knee flexor strength compared to those in the uninjured contralateral limb, 7,13 which may partially explain why a previous HSI is the primary risk factor for future injury. 2Currently, the gold standard measure for the assessment of eccentric knee flexor strength is isokinetic dynamometry. 1 However, this technique is limited by the high cost of the device and, therefore, its lack of widespread availability. Although handheld dynamometers have become a popular field-based alternative, they require operator skill and strength to collect reliable and valid data. 22The purposes of this investigation were (1) to determine if a novel device, designed to measure eccentric knee flexor strength via the Nordic hamstring exercise (NHE), would display acceptable test-retest reliability; (2) to determine normative values for eccentric knee flexor strength derived from the device in in-T T STUDY DESIGN: Reliability and case-control injury study. T T OBJECTIVES:To determine if a novel device designed to measure eccentric knee flexor strength via the Nordic hamstring exercise displays acceptable test-retest reliability; to determine normative values for eccentric knee flexor strength derived from the device in individuals without a history of hamstring strain injury (HSI); and to determine if the device can detect weakness in elite athletes with a previous history of unilateral HSI. T T BACKGROUND: HSI and reinjury are the most common cause of lost playing time in a number of sports. Eccentric knee flexor weakness is a major modifiable risk factor for future HSI. However, at present, there is a lack of easily accessible equipment to assess eccentric knee flexor strength. T T METHODS:Thirty recreationally active males without a history of HSI completed the Nordic hamstring exercise on the device on 2 separate occasions. Intraclass correlation coefficients, typical error, typical error as a coefficient of variation, and minimal detectable change at a 95% confidence level were calculated. Normative strength data were determined using the most reliable measurement. An additional 20 elite athletes with a unilateral history of HSI within the previous 12 months performed the Nordic hamstring exercise on the device to determine if residual eccentric muscle weakness existed in the previously injured limb. T T RESULTS:The device displayed high to moderate reliability (intraclass correlation coefficient = 0.83-0.90; typical error, 21.7-27.5 N; typical error as a coefficient of varia...

Effects of a 10-Week In-Season Eccentric-Overload Training Program on Muscle-Injury Prevention and Performance in Junior Elite Soccer Players

“…However, despite the difficulty in matching the intensities between the NHE and the YoYo leg-curl exercise, it seems that the YoYo leg curl provides a much higher eccentric overload than the NHE. 20,21 Furthermore, the eccentric-concentric transition phase is completely different in the exercises. Therefore, due to the wide spectrum of advantages, it might be recommended to include these exercises with flywheel devices.…”

The Relationship between Previous Lower Extremity Injury, Body Weight and Bilateral Eccentric Hamstring Strength Imbalance in Young Soccer Players

“…Strength imbalance can be characterized by either side-to-side (right versus left ) or front-to-back (agonist versus antagonist) diff erences in muscle length or strength. As a gold standard, isokinetic dynamometers have commonly been used over the years to measure strength and to assess muscle strength imbalance (Mijnarends et al, 2013), but these methods have some disadvantages, such as lack of portability and high cost of their widespread use (Opar, Piatkowski, Williams, & Shield, 2013). To overcome these limitations, a number of testing systems have been developed.…”

ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION & THE HAMSTRINGS Implications for injury prevention & rehabilitation

“…Moreover, athletes with a history of ACL injury or HSI have been found to display similar eccentric knee flexor weakness and shorter BFLongHead fascicle lengths in the previously injured limb compared to the uninjured contralateral limb (Opar, Piatkowski, et al, 2013;Timmins et al, 2016a). These findings suggest that a prior ACL injury and HSI may both significantly increase the risk of future HSI.…”

“…Participants were instructed to perform each eccentric repetition at the slowest possible speed and were loudly encouraged to provide maximum effort during each repetition. During the familiarisation session, the Nordic hamstring exercise was performed, with body mass only, on a device described previously which enabled forces at the ankle to be assessed (Opar, Piatkowski, Williams, & Shield, 2013;Opar et al, 2015aOpar et al, , 2015b. The ankle braces and load cells attached to the device allowed the forces generated by the knee flexors to be measured through the long axis of the load cells.…”

“…The assessment of eccentric knee flexor strength using the Nordic hamstring testing device ( Figure 5-1) has been reported previously (Bourne et al, 2016;Opar, Piatkowski, et al, 2013;Opar et al, 2015a;Timmins et al, 2016b). Athletes knelt over a padded board, with ankles secured immediately superior to the lateral malleolus by individual ankle braces, which were attached to custom made uniaxial load cells (Delphi Force Measurement, Gold Coast, Australia) with wireless data acquisition capabilities (Mantracourt, Devon, UK).…”