Determination of upper and lower limb coordination in freestyle swimming using

body-fixed sensors

C. Nieuwstad & J.M. Barden

Neuromechanical Research Centre, Faculty of Kinesiology & Health Studies, University of Regina,

Regina, Saskatchewan, Canada

Acknowledgement: The authors would like to thank Swim Saskatchewan and GENEActiv

for their support of the project, in addition to those swimmers who participated in the

study during the Swim Saskatchewan High Performance camp.

Presented at the SPIN Summit (organized by Own the Podium), September 16th to 18th, 2013,

Calgary, Alberta, Canada. For further information contact Craig Nieuwstad at

nieuwsycraig@gmail.com or Dr. J. Barden at john.barden@uregina.ca.

Introduction

Apparatus

Results (cont.)

Results

Methods

Discussion & Conclusion

References

• Research has shown that a swimmer’s arms create the majority of propulsive

force required for movement through the water (Deschodt et al., 1999).

• This has led to multiple studies being conducted on how the stroke parameters

(stroke rate and stroke length) contribute to front crawl swimming performance. • Recently, a number of researchers have used body-fixed sensors in an attempt to

overcome the considerable limitations associated with using video analysis to

quantify stroke parameters.

• Several studies have validated the use of accelerometer-based sensors to measure

stroke parameters in elite competitive swimmers which allow for the continuous

capture of data (Davey et al., 2008; Callaway et al., 1999).

• The majority of this research, however, has only looked at upper body stroke

parameters, while the lower body and how it contributes to the complete

performance of the stroke has not been investigated.

• The literature on the front crawl leg kick has been limited to kicking mechanics

with little consideration for its effect on the arm stroke cycle.

• This is further demonstrated by the fact that coordination is identified by the

relative time lags between the left and right propulsive phases of the arm stroke

(Chollet et al., 1999).

• Front crawl swimming is a whole body movement and coordination should not be

quantified by only investigating one portion of that movement.

• Therefore, the purpose of this study was to determine whether accelerometers can

be used to identify coordination patterns between the arms and legs during front

crawl swimming.

• Two GENEActiv tri-axial accelerometers sampling at 60 Hz were placed on the

dorsal surface of the wrist and the posterior surface of the ankle of each

swimmer’s non-preferred breathing side. At the wrist, the Y-axis aligned with the

long axis of the forearm and the X-axis created a perpendicular line across the

distal radioulnar joint. At the ankle, the Y-axis aligned with the long axis of the

leg and the X-axis created a mediolateral line through the malleoli of the ankle

(see Fig. 1).

• Two GoPro Hero3 cameras sampling at 60 Hz were used to record the trials and

were placed above and below the water using a GoPole.

Subjects

• Two swimmers (1 male, 1 female) selected for the Swim Saskatchewan Youth

High Performance camp participated in this pilot study.

Protocol

• The study took place in a 25 m pool.

• Participants performed a sub-maximal 30-minute warm-up prior to testing.

• Participants were instructed to perform one 25 m front crawl swim at their

maximum velocity.

Maglischo six-beat kick coordination model

• This model (Maglischo, 2003) proposes the following:

a) A downsweep of the left arm accompanies a downbeat kick with the left leg.

b) An insweep of the left arm accompanies a downbeat kick with the right leg

(or an upbeat kick with the left leg).

c) An outsweep of the left arm accompanies a downbeat kick with the left leg.

Data Analysis

• Raw X (wrist) and Z (ankle) accelerations were synchronized and processed

using a low-pass digital filter with a cut-off frequency of 4 Hz.

• The different phases of the arm stroke (entry, downsweep, insweep, outsweep

and recovery) and leg kick (up/down beat) cycles in the accelerometer data were

identified using video.

• Accelerometer-based time intervals between arm and leg stroke cycle events were

then used to quantify coordination and compared to Maglischo’s model.

1. Callaway, A.J. et al. (2009). Int J Sports Sci Coach, 4:139-153.

2. Chollet et al. (1999). Int J Sports Med, 20:54-59.

3. Davey, N. et al. (2008). Sports Technology, 1: 202-207.

4. Deschodt, V.J. et al. (1999). Eur J Appl Physiol, 80:192-199.

5. Maglischo, E.W. (2003). Swimming Fastest. Champaign: Human Kinetics.

Figure 2. One stroke cycle depicting the arm stroke and leg kick phases.

Figure 3. Arm and leg coordination over 5 stroke cycles for both the male and female participant.

Figure 1. Axis alignment of the accelerometer on the wrist and ankle.

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0

1

2

3

4

0.02 0.22 0.42 0.62 0.82 1.02 1.22 1.42 1.62 1.82 2.02 2.22 2.42 2.62 2.82 3.02 3.22 3.42 3.62 3.82 4.02 4.22 4.42 4.62 4.82 5.02 5.22 5.42 5.62

Accele

rati

on

(g

)

Time (s)

Female swimmer: Five stroke cycles Leg Arm

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1

2

3

4

0.02 0.22 0.42 0.62 0.82 1.02 1.22 1.42 1.62 1.82 2.02 2.22 2.42 2.62 2.82 3.02 3.22 3.42 3.62 3.82 4.02 4.22 4.42 4.62 4.82 5.02 5.22 5.42 5.62

Acc

ele

rati

on

(g

)

Time (s)

Male swimmer: Five stroke cycles Leg Arm

• The results demonstrate that the phases of the arm-stroke cycle and the leg kick are

easily identifiable when using accelerometer-based data.

• According to Maglischo’s qualitative model, both participants exhibited an

incorrect coordination between the stroke cycle and the kick cycle throughout the

25 m.

• More specifically, both participants executed their propulsive arm phases

prematurely with respect to the accompanying downbeat or upbeat kick.

• This suggests that the participants are losing the maximum propulsion that could be

gained during the stroke cycle if their propulsive phases were synchronized with the

kick cycle.

• Future studies should consider the use of a hip accelerometer to investigate the loss

of forward velocity during an uncoordinated stroke cycle.

• The downsweep phase of the arm stroke occurs prior to the downbeat of the kick.

• Male: 0.181(± 0.023) seconds; Female: 0.112 (± 0.046) seconds

• The insweep phase of the arm stroke occurs prior to the upbeat of the kick.

• Male: 0.061 (± 0.022) seconds; Female: 0.051 (± 0.017) seconds

• The outsweep phase of the arm stroke occurs prior to the downbeat of the kick.

• Male: 0.11 (± 0.023) seconds; Female: 0.093 (± 0.024) seconds

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0.5

1.5

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0.02 0.08 0.15 0.22 0.28 0.35 0.42 0.48 0.55 0.62 0.68 0.75 0.82 0.88 0.95 1.02 1.08 1.15 1.22 1.28

Ac

ce

lera

tio

n (

g)

Time (s)

One stroke cycle

Leg

Arm

Downbeat

Upbeat

Downsweep

Insweep

Upsweep

Recovery

Entry

X +

X +

Y +

Z +

Y + Z +