2007, Piran, Slovenia

Environmental Ergonomics XII
Igor B. Mekjavic, Stelios N. Kounalakis & Nigel A.S. Taylor (Eds.), © BIOMED, Ljubljana 2007
QUANTIFYING THE SKILL COMPONENT OF SWIMMING IN THE
SEA ENVIRONMENT
Tara Reilly, Alun Rees, Frank Golden, Greg Spray, Michael Tipton
Department of Sport & Exercise Science, Institute of Biomedical & Biomolecular Sciences,
University of Portsmouth, UK
Contact person: tara.reilly@port.ac.uk
INTRODUCTION
In the UK a beach lifeguard working for the Royal National Lifeboat Institution (RNLI) is
expected to be able to run and swim 200m out to sea within 3.5 minutes in order to rescue
someone in danger of drowning (Reilly et al, 2004). Due to the differences in the geology of
surf beaches (SB) and non-surf beaches (NSB), lifeguards are able to run further out to sea
before swimming on SB (they are shallower). So, despite the more adverse swimming
conditions on SB, on average, it takes about the same time to reach a casualty at 200m on
both SB and NSB (Reilly et al, 2004). The ability to run further out to sea on a SB disguises
the greater demands associated with swimming in surf. Anecdotally, swimming in the surf
requires a set of skills not associated with pool swimming. However, the capability of a beach
lifeguard to reach a casualty in the surf is assessed by their ability to swim in a pool.
This paper attempts, for the first time, to determine the extent of the skill component in surf
swimming by examining the comparative sea swimming performance of lifeguards with high
and low levels of surf swimming experience. The ability to predict swimming performance
on the basis of pool swim times, self-reported surf experience, anthropometry and anaerobic
performance on a swim bench was examined. It was hypothesised that surf swimming
involves a quantifiable skill component (H1), and the ability to swim in the surf can be
predicted from easy to measure land-based tests (H2).
METHODS
Sixty-five beach lifeguards (BLG) volunteered for the study, which received ethical approval
from the University of Portsmouth Ethics committee. The lifeguards came from SB and NSB,
their surf swimming experience was assessed by a questionnaire designed specifically for the
project, and which examined the frequency and severity of surf swimming experience to
produce a score for each lifeguard on a scale from 0-310. On the basis of this score, the BLG
were divided into two distinct groups, 30 BLG had no or little surf swimming experience
(NSE, score of 0-85); and 35 had a high level of surf swimming experience (SE, score of
110-310). The BLG with NSE had an average (SD) score on the surf experience
questionnaire of 25 (26); the corresponding score for the BLG with SE was 267 (61).
Each BLG undertook the following tests:
a. An initial 200m pool swim (PS1), maximum effort (25 metre pool). Data collected 8 weeks
before the sea swims (see below).
b. A 200m swim in calm sea water (CSS) (Gyllingvase, Falmouth, UK), maximum effort.
c. A 200m swim in surf conditions (SSS) (Perranporth, Cornwall, UK), maximum effort.
d. A final 200m pool swim (PS2), maximum effort (25 metre pool)
e. A maximum effort 25m underwater/25m pool swim
f. Ergometer test. A 30s swim bench test (Weba Sport Expert, Swim Bench, Austria).
g. Anthropometry. The following measurements were taken: height, weight, arm length
(Chatard et al, 1992), shoulder circumference, skinfold thickness (4 sites; Durnin &
Womersley, 1974; Costill et al, 1985).
The environmental conditions at Gyllingvase were: Zero metres wave height; 16°C water
temperature; 16°C air; 16-18°C air temperature. The environmental conditions at Perranporth
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