Predicting Eccentric Hamstring Strength from Nordbord and Ultrasound Characteristics: A Preliminary Study

Hamstring strength is integral to stability and function in the body. Adequate eccentric hamstring strength (EHS) is an important factor in reducing injury potential in athletes. Currently no studies report on EHS in recreationally active adults. A pilot study was conducted to investigate the connections between EHS and injury potential. PURPOSE: Evaluate the association of eccentric hamstring total force with age, sex, volume, height (cm), weight (kg), average echo intensity (EI), and total hours of physical activity per week (TPA). METHODS: Eleven recreationally active individuals (age: 24.2 ± 4.8 y, ht: 175.4 ± 11.7 cm, wt: 73.2 ± 15.5 kg, F = 5) had their hamstrings imaged at 50%, 60%, 70% the distance between greater trochanter and the knee joint using ultrasound. Hamstring cross sectional area (CSA) and EI in each image were measured twice with Osirix MD. The Nordbord device was used to measure EHS. Hamstring volume was estimated using the truncated cone formula. Various linear models were assed to develop one that will be used for future participants. RESULTS: Our initial proposed linear model had an adjusted r2 = 0.75, with F-statistic: 5.2, 7 and 3 DF, p= 0.0997. Only weight had a near-significant impact (p=0.064). After removing age and replacing TPA with weekly hours of moderate physical activity (mPA), our model returned adj r2 = 0.87, F-stat: 12.04, 6 and 4 DF, p = 0.0154. In this model, weight (p=0.014) and EI (74.5 ± 15.5) (p=0.023) were significant, and height (p=0.080), sex (p=0.064), and volume (542 ± 139 cm3) (p= 0.051) approached significance. This model was more predictive within the sample. CONCLUSION: Total force of EHS was only affected by weight in the first model but affected by weight and EI in the updated model. More impactful variables will be needed to create a more generalized model to investigate the association between EHS and injury risk. A future project will include participants through 80 years of age. In that study, age is hypothesized to impact EHS.