Oslo Sports Trauma Research Center

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Information about project titled 'A new method for strength and power testing used for monitoring rehabilitation, performance and training'

A new method for strength and power testing used for monitoring rehabilitation, performance and training

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Project status: Published
Project manager: Jo Inge Gåsvær
Supervisor(s): Roald Bahr

Description

In sport and research there is a need for accurate methods to measure performance during dynamic muscle action. Isokinetic and isometric devices with good accuracy exist, but the validity of such measurements may be questioned. A new multi-function measuring device, the Musclelab® apparatus, has recently been developed to measure velocity, force and power during dynamic muscle action. Since measurements can be done using free weights or dynamic strength training equipment for most muscle groups, it may be assumed that the relation to sport performance is closer than what is reported for other strength testing instruments. The aim of this study was to determine the reproducibility of velocity, force and power measurements during a dynamic squat, as well as various jump tests.

 

Methods: Forty-eight subjects (14 elite athletes, 12 trained and 22 sedate subjects) were tested three days in a row. The first test session was a familiarization session, where one repetition maximum (1 RM) in a 90 degree squat was determined. In the two final test sessions the subjects performed concentric squats with loads of 15%, 30%, 45%, 60%, 75% and 90% of their individual 1 RM. Velocity, force and power were measured using the accelerometer or linear encoder of the Musclelab device. The subjects also performed standing vertical jumps (SJ), counter movement jumps (CMJ), and standing jumps with a load of 50% of their body weight (SJ50%). Jump height was determined from flight time measured on a contact mat.

 

Results: The test-retest coefficient of variation (CV) varied between 3.0% and 6.6% (average velocity), 0.4% and 1.9% (average force), and 3.6% and 6.5% (average power). For SJ, CMJ and SJ50% the CV for jump height was 4.6%, 5.3% and 6.1%, respectively.


Conclusion: The test-retest reproducibility for average velocity, force and power during dynamic squats using the Musclelab device was as good or better than what is reported for other strength testing instruments.