The effect swimming training intensity has on sleep, mood and recovery in elite swimmers
Date
2020
Authors
Pretorius, Shandré
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Abstract
BACKGROUND: Swimming is dynamic in nature and utilises both anaerobic and aerobic
energy systems, and is a sport in which elite athletes often reach their peak physiological
performance. Recovery has been found to encompass five factors; sleep, nutrition and hydration,
psychological and emotional state, and active cooldown. Sleep forms one of the main
components and if an athlete has poor sleep quality and quantity it may have a negative
cascading effect on the physiology involved in the recovery process. Sleep quality and the
components of the Total Quality Recovery (TQR) score are all interlinked and dependent on
each other in the cycle of recovery. When an individual has slept for 8 hours and is in a positive
mood during training and competitions the swimmers performance improves. Although recovery
measures have been studied in elite swimmers, quantifying each factor at an individual level by
using the TQR, mood and sleep measures will add to the knowledge of optimising swimmers
performance.
OBJECTIVE: To determine the effect swimming training intensity has on elite swimmers by
assessing sleep, mood, performance and recovery.
METHODS: A quantitative, explorative analytical study was conducted to assess the effect that
swimming training intensity has on sleep, mood, performance and recovery in 15 elite swimmers
between the ages of 13-21 years with a mean age of 16±2.09 years. Individuals were required to
wear a Fitbit™ device on their non-dominant wrist for the duration of the 14 week study to
measure daily calories expenditure, steps, active minutes, distance walked , total sleep time
(TST), restless minutes, rapid eye movement (REM), none rapid eye movement (NREM), light
and deep sleep, exercise and resting heart rate (RHR). In addition they completed the following
questionnaires daily- Total Quality recovery (TQR) and Sleep Diary (SD), and weekly the
Wellness Questionnaire and the Profile of Mood States (POMS). The Pittsburg Sleep Quality
Index (PSQI), Sleep Hygiene Index (SHI) and Morningness-Eveningness Questionnaire (MEQ)
were completed every four weeks and lastly the Sports Emotional Questionnaire (SEQ) was only
completed when the athlete swam in an event. Participants completed self-reported
questionnaires and Fitbit data was automatically collected. All data was collected by the
researcher on a weekly basis. Statistical analysis was performed using Statistica version 10. The
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demographics were expressed as mean, median and interquartile ranges and descriptive analysis
was used to describe the interrelationships of the PSQI, SHI, MEQ, SD, TQR, training intensity
and performance, in order to illustrate the relationship between sleep, performance, mood and
recovery. A pilot study on 8 participants was conducted using a similar methodology used to
optimise the main study, and in the main study the same model Fitbit in addition to a different
model was used in the latter part: hence the two studies are analysed and reported separately.
RESULTS: 15 participants were included in the final analysis of the main study; with the mean
age of participants 16±1.81 years with competitive swimming years mean of 6.7±2.71 years.
Data analysis in the pilot study was performed on 8 participants, with a mean age of 16±2.78
years and mean of 6.5±3.33 years of competitive swimming. DROPOUT RATE: 11.76% drop
out of participants was observed with 2 participants being excluded from the main study due to
incomplete data. In the pilot study there was a dropout rate of 46.67% with 7 participants being
excluded. SLEEP: A 52% and 13% decrease in FB TST was found in the main and pilot study.
A steadily increase in sleep efficiency was observed in the main (60%) and pilot (46%) studies.
SD TST compared to FB TST in the main (p=0.006) and pilot (p=0.03) study. MOOD: A
progressive increase in depression and decrease in vigour was observed in the main (5%; 4%)
and pilot (6%; 5%) studies. Participants experienced a pleasant mood state throughout the
duration of the main and pilot studies. PERFORMANCE: An average RHR of 63.43 beats per
minute (bpm) was found in the main study. Performance times during training and competitions
improved in the main (1.345 seconds; 0.04 seconds) and pilot (3.545 seconds; 7.465 seconds)
study. RECOVERY: Each TQR component fluctuated during the main and pilot studies. The
only component that remained relatively steady in the pilot study was water consumption.
CONCLUSION: It was found that TQR recovery directly reflected a swimmers’ performance,
during training cycles with changes in training intensity. A strong assumption can be made that
the sleep and mood factors can influence performance through recovery. This study could
effectively link aspects of sleep quality and quantity to recovery and that mood had an effect on
performance during training and competitions. Therefore, this study was able to find a
relationship between sleep, mood, recovery and performance
Description
A dissertation submitted in fulfilment of the requirements for the degree of Master of Science in Medicine to the Faculty of Health Sciences, School of
Therapeutic Sciences, University of the Witwatersrand, Johannesburg, 2020