Psychometric and Physiological Responses to a Pre-season Competitive Camp in the Heat With a 6-hr Time Difference in Elite Soccer Players
Buchheit, M., Cholley, Y., Lambert, P.
Purpose: The aim of the present study was to examine in elite soccer players some psychometric and
physiological responses to a competitive camp in the heat, after travelling across 6 time-zones. Methods:
Data from 12 elite professional players (24.6±5.3 yr) were analyzed. They participated in an 8-day pre-
season summer training camp in Asia (heat index 34.9±2.4 0C). Players’ activity was collected during all
training sessions and the friendly game using 15-Hz GPS. Perceived training/playing load was estimated
using session rate of perceived exertion (RPE) and training/match duration. Psychometric measures of
wellness were collected upon awakening before, during and after the camp using simple questionnaires.
HR response to a submaximal 4-min run (12 km/h) and the ratio between velocity and force load
(accelerometer-derived measure, a marker of neuromuscular efficiency) response to 4 ~60-m runs (22-24
km/h) were collected before, at the end and after the camp. Results: After a large increase, the RPE/m.min-
1
ratio decreased substantially throughout the camp. There were possible small increases in perceived
fatigue and small decreasesin subjective sleep quality on the 6th day. There were also likely moderate (~3%)
decreases in HR response to the submaximal run, both at the end and after the camp, which were
contemporary to possible small (~8%) and most-likely moderate (~19%) improvements in neuromuscular
efficiency, respectively. Conclusions: Despite transient increases in fatigue and reduced subjective sleep
quality by the end of the camp, these elite players showed clear signs of heat acclimatization, which were
associated with improved cardiovascular fitness and neuromuscular running efficiency.