This study examined the effects of heat on cycling performance. Eight cyclists completed submaximal and 5-minute maximal cycling trials in both normal and heated conditions. Core temperature, heart rate, perceived exertion and other physiological measures were taken throughout. During the maximal trials, cyclists generated significantly higher average power and did more total work in the normal condition compared to the heated condition. The study found that increased heat stress negatively impacted cycling performance.

1. A SUB MAXIMAL AND 5 MINUTE MAXIMAL POWER CYCLE TIME TRIAL
Max Burrows, 1105960
University of Chichester, UK.
INTRODUCTION
METHOD
Participants
The participants (N=8) were undergraduates (aged 22±1). Anthropometric
characteristics were as follows: Height (181±7cm) and body weight (81.5±8kg).Participants
partook in a repeated measure, cross over design: controlled cycle and experimental
cycle. Participants were recruited from a previous long distance cycling journey.
After giving consent the participants were randomly assigned to either the control
cycle or the experimental cycle.
Procedure
The controlled cycle was conducted at (21± 1°) room temperature, (…) % humidity and
(…..) barometric pressure. The experimental cycle was performed within a TISS model
environmental chamber at 32 ±1°, 65% humidity and (…..) barometric pressure. Pre
experiment (table 1) participants had inserted a rectal thermistor (Tre) and placed skin
thermistors on their forehead (T2) and on the back of their left hand (T3) these were
connected to an edale thermistor thermometer. The participants had their core and
peripheral temperatures monitored throughout the experiment, if Tre rose higher than 38.5°
the experiment was stopped. Furthermore measurements of heart rate (HR), Blood lactate
(mmol/L); rate of perceived exertion (RPE), gut fullness (GFS), thermal comfort (TC) were
taken and hydration status (SG).
The participants cycled on a monark cycle ergometer equipped with foot straps. They were
asked to maintain a frequency of 60 revolutions per minute (RPM) in both designs with a
40% resistance which was determine in a previous incremented max power test.
Measurements taken from ‘pre experiment’ were taken every 10 minutes (stages 1, 2, 3 and
4, table 1). Also the participants were given 250ml of water to maintain hydration and
weight. After stage 4, the participant engaged in a 5 minute maximal power cycle in which
the monark cycle ergometer was interfaced with (COMPUTER NAME) in which the data
was collected.
Statistical Treatment
Differences between the two conditions were assessed using paired samples t-tests for
average power, total work done, climbing time and distance travelled by climber’s center of
mass.
Table 1. Relationship between Core, Head and Hand temperature between
conditions.
Significant positive linear relationships were found between salivary cortisol
concentration and both performance measures of climbing time and distance
travelled by climber’s CoM. Higher cortisol concentrations were associated with
slower climbing and less direct movement. Higher cortisol concentrations were
also associated with higher anxiety ratings. This study is important in making a link
between subjective experiences, biochemical stress markers and motor
performance during a complex physical task. Previous studies had established a
link between situation and stress during rock climbing but no study had examined
the relationship between these variables and motor performance..
CONCLUSIONS
The increased stress of the high climb condition appears to have had a significant
impact on anxiety rating and movement based variables. Changes occurred in the
direction expected: more stressful conditions eliciting greater anxiety and poorer
climbing performance.
RESULTS
Average power rating (Watts) was significantly different
(t7 = 4.147, p = .004).
Figure 1. Average power during each cycling
condition.
Total work done measures were significantly different
between conditions; (t8 = 4.853, p = .001) Cyclists were
able to cycle at a higher intensity for longer in the normal
condition.
Figure 2. Total work done during 5 minute max power
cycle.
Figure 3. Distance of travel of center of mass during
each climbing condition
REFERENCES
Performance Measure F Value Significance
Thermistor Thermoneutral
Thermistor High Temperature
Table 1. The experimental design conducted in both environments.
0
50
100
150
200
250
AveragePower(Watts)
High TemperatureThermoneutral
0
10
20
30
40
50
60
70
80
TotalWorkDone(Watts)
High TemperatureThermoneutral