Indoor Biofeedback Analysis for Rowing

Introduction

The 3rd Year students of the BE in Sports and Exercise Engineering at NUI Galway, Ireland, investigated the relationship between the angle of flexion of the knee to acceleration of the pelvis and the acceleration of the hands. From this the relationship between the overall acceleration of the rower was compared to the angle of flexion of the knee. The project’s client was the NUI Galway Rowing Club with the Head Coach Mr. Dave Mannion being the club contact. The project was carried out under the supervision of Prof. Gearóid Ó Laighin, the Professor of Electronic Engineering.

Methods

To determine joint angle during rowing the Xsens MVN BIOMECH was used. It was chosen as it is easy to use, it outputs instantly various joint angles, is highly flexible and it can export the data easily to be processed in MATLAB.

As a general rule coaches often tell their athletes to end the recovery phase of their stroke when their lower leg is vertical however rowers often say that they usually go beyond that point to get a better push off and larger acceleration. The MVN Biomech was used to investigate if there was a relationship between the angle of flexion of a rower’s knee at the catch phase of the stroke and their maximum acceleration during the drive phase on an indoor rowing machine.

By adjusting the angle of flexion the varying acceleration at both the pelvis and hands were analyzed. For the study, the sample size was five subjects, three of the subjects were athletes who row competitively with the University’s rowing club while the remaining two subjects were athletes from the other sports who use rowing machines occasionally but have no experience of rowing competitively.

During the first period of rowing the subject was asked to slide the seat as far as they comfortably could at the catch phase of each stroke in order to maximize flexion of their knees. This point was marked at the maximum knee flexion. For the next periods of rowing, a stopper was placed on the rowing machine at 2cm increments for each period of rowing. The rower was asked to row for 15s for each phase of the experiment. This process was repeated until the stopper reached 20cm from the initial point resulting in five sets of data.

Results

indoorrowingpicture1indoorrowingpicture2

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Analysis of the data showed a direct relationship between knee flexion and the initial acceleration of the pelvis. For the three elite rowers there was a decrease in pelvis acceleration as the angles of flexion at the catch phase was reduced. The rowers felt their natural stroke was being restricted as their angle of flexion was limited which can be seen from the graphs. Unlike the acceleration of the pelvis, it was found that there was an inverse relationship between knee flexion and initial acceleration of the hands in two of the three elite rowers. One explanation for this result is that the rowers may have used their upper body to compensate for the restricted knee flexion. This theory was supported as the rowers admitted that they increase their upper body work load.

Team

Professor Gearóid ÓLaighin,
Professor of Electronic Engineering,
NUI Galway,
Galway,
Ireland
E: [email protected]

Damien Kelly,
Project Leader,
Sports and Exercise Engineering,
NUI Galway,
Galway,
Ireland
E: [email protected]

Paul Ruane,
Sports and Exercise Engineering,
NUI Galway,
Galway,
Ireland
E: [email protected]

Paul Burke,
Electronic and Computing Engineering,
NUI Galway,
Galway,
Ireland
E: [email protected]

Thomas Curtin,
Electronic and Computing Engineering,
NUI Galway,
Ireland
E: [email protected]

> Website NUI Galway


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