Reliability of a Cycle Sprint Test to Measure Lower Limb Muscle Power

Research Article

Phys Med Rehabil Int. 2021; 8(4): 1189.

Reliability of a Cycle Sprint Test to Measure Lower Limb Muscle Power

Edmondston SJ¹*, Gibbons R¹, Mackie KE¹, Haywood Z¹, Hince D² and Hurworth M³

1Murdoch Centre for Orthopaedic Research, St John of God Murdoch Hospital, Murdoch, WA 6150, Australia

2Institute for Health Research, University of Notre Dame, Australia

3Murdoch Orthopaedic Clinic, St John of God Murdoch Hospital, Australia

*Corresponding author: Stephen Edmondston, Murdoch Centre for Orthopaedic Research, St John of God Murdoch Hospital, 100 Murdoch Drive, Murdoch, WA 6150, Australia

Received: July 15, 2021; Accepted: August 31, 2021; Published: September 07, 2021

Abstract

This study examined the reliability of a cycle sprint test for measuring lower limb muscle power. Twenty asymptomatic volunteers completed the test on two occasions, with one week between test sessions. Participants sat on a stationary road bicycle with commercial power meters in the pedal cranks. Maximum and average muscle power was measured during three, 10-second sprint efforts. The test demonstrated excellent within- and between-day reliability for both maximum and average power measurement (ICC=0.93 to 0.97). The within-day Standard Error of Measurement (SEM) was between 25.9W (6.1%) and 35.1W (8.5%), and 24.8 (6.5%) and 28.6W (7.7%) for maximum and average power respectively. The between-day SEM was 34.3W (7.8%) for maximum power and 26.4W (7.1%) for average power. Reliability of the cycle sprint test has been established, along with thresholds for significant change. The cycle sprint test may have relevance in clinical populations to evaluate lower limb muscle power following injury, or to measure rehabilitation outcomes.

Keywords: Lower limb; Muscle power; Reliability; Functional outcomes; Cycle sprint test

Introduction

The impact of lower limb pathology and related functional deficit is commonly measured using patient-reported and physical function measures [1-3]. Since the loading environment of the knee joint is dependent on muscle function, it has been suggested that muscle function be evaluated in all patients with knee pathology [4,5]. Muscle function encompasses both strength and power. Muscle power is defined as “the product of dynamic muscular force and muscle contraction velocity”, ([6] p3167) and has been found to be superior to muscle strength as a predictor of functional performance in healthy adults and patients with knee pathology [7,8].

Muscle strength tests examine maximal exertion of a single muscle, often using open kinetic chain dynamometry [9,10]. However, closed kinetic chain measurement techniques may more closely reflect functional tasks. Aalund et al. [11] reported that leg press power was more closely associated with physical performance than quadriceps strength following knee arthroplasty. These findings highlight the potential importance of closed-chain evaluation of muscle power as an outcome measure in patients with knee pain or following intervention [11,12]. However, there has been limited documentation of reliable methods of muscle power evaluation that may be relevant in clinical populations, including older individuals.

Using a commercial power meter fitted to a standard road cycle, we have developed a cycle sprint test to assess lower limb muscle power. This test may support the evaluation of muscle power in clinical populations, particularly in monitoring outcomes of surgical treatment and rehabilitation. Before introducing this new method into clinical practice, there is a need to examine the acceptability and reliability in healthy participants, and to define thresholds for significant change. The aim of this study was to examine the reliability of a stationary cycle sprint test to assess lower limb muscle power in healthy individuals.

Methods

The study participants were healthy volunteers with no history of knee pain or symptoms of knee osteoarthritis. A minimum age of 18 years and adequate English were required to take part in the study. Participants were excluded if they had a history of previous lower limb surgery, unstable cardiovascular or respiratory conditions. Participants were provided information regarding the study and those who agreed to participate provided written consent. All procedures performed in this study involving human participants were in accordance with the ethical standards of the institutional committee that have approved them.

Muscle power was measured using the InfoCrank Power Meter (Verve Cycling, Australia). The InfoCrank has an absolute maximum error of 0.11Nm below 17Nm and 0.57% above 17Nm, indicating that it is highly accurate within and between sessions [13]. The InfoCrank replaces the standard cranks on a bicycle and contains dual sided power meters that communicate with one another and function as one. This device directly measures torque applied to it via plastic deformation of the strain gauges under load and cadence (RPM). Power and cadence was collected at 256Hz and transmitted to an ANT+ receiver, in this case an O_Synce Navi2coach bike computer (O_Synce, Germany). Data was analysed using a cycling analysis software program, Golden Cheetah for Windows (GoldenCheetah v3.4), and exported to Microsoft Excel for Windows to calculate the average and maximum power for each test.

A repeated measures design with seven days between tests was used. Testing was performed with the participant seated on a road bicycle (Pinarello, Italy) mounted on a stationary trainer (Revbox Erg, New Zealand). The participants were fitted to the bicycle with a clipless pedal and standardized downstroke knee angle of 25 degrees (Figure 1) [14]. Participants were asked to perform a familiarization session of 1 minute on the bicycle to gain confidence and ensure comfort. For each participant, seat height and the self-selected gear setting were consistent on both testing days. Following the familiarization session, the participant was asked to perform a sprint of 10 seconds followed by a one-minute recovery. For the ‘sprint’ phase, the participant was instructed to ‘pedal as hard and fast as you can’. The participants had either passive recovery (no pedalling) or active recovery (light pedalling) between each sprint based on their preference, and this was consistent between trials and within test days. The sprint/rest phases were repeated two more times. The testing for each participant was carried out at approximately the same time of day, to reduce the possible impact of circadian rhythm on test performance [15,16].