Predicting hamstring muscle strength from Nordic Hamstring Curl break point using iPhone accelerometry


Equipment to determine hamstring strength can be expensive and is unlikely to be widely adopted within physiotherapy practices.  This study used accelerometers to define when participants “fell” (break angle) when completing a Nordic hamstring curl, and will attempt to create an equation based on participant height, weight and break angle to estimate hamstring strength with their iPhone.

180 hockey players completed the Nordic Hamstring Curl with an iPhone 8+ attached to their hip.  Strength of the hamstring muscles was determined by the NordBord hamstring dynamometer, and break angle was determined by the acceleration of the iPhone as the participants lowered themselves to the ground.  Statistics will be completed to create an equation that will estimate the strength of the hamstring muscles from the iPhone data and the individual’s height and weight.

This study aims to develop a cost effective app or equation-based method to estimate hamstring strength during the Nordic hamstring curl from patient’s height, weight, and break angle during the exercise.  This can be used to determine strength levels for safe return to play following hamstring strain or to track changes in strength with training.

Researchers: Dan Ogborn, Alix Bellemare, Brittany Bruinooge