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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Date data sharing statement initially provided
Date results information initially provided
Type of registration
Retrospectively registered

Titles & IDs
Public title
Effect of partial-body cryostimulation after training on sleep quality in professional soccer players
Scientific title
Effect of partial-body cryostimulation after training on sleep quality in professional soccer players
Secondary ID [1] 297444 0
Nil khnown
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
-Hypertension 311796 0
-arterial disease 311797 0
-Myocardial infarction less than 6 months 311798 0
-Respiratory condition (asthma, bronchopneumopathy) 311799 0
-Circulatory insufficiency (Raynaud's syndrome) 311800 0
-Angina pectoris 311801 0

-Pace maker or subcutaneous device
311802 0
-Deep vein thrombosis / phlebitis 311803 0
-Nephritic colic, hepatic colic 311804 0
-Hyperuricemia (gout attack) 311805 0
-Cold allergy 311806 0
-Cutaneous infection (acute bacterial or viral) 311807 0

-Acute infection
311808 0
Condition category
Condition code
Physical Medicine / Rehabilitation 310255 310255 0 0
Occupational therapy

Study type
Description of intervention(s) / exposure
each player experienced different exposure durations at -180°C in a partial-body chamber (Cryotechno®, Castelnau le Lez, France) in a random order (no cryostimulation, 180-s exposure, twice 90-s exposure separated by a 5-min rest at room temperature, and 90-s exposure). These exposures are separated by a Week. A partial-body chamber consists of an open tank in which the subject is exposed to cold, excluding the head and neck. The cold temperature is obtained by spraying nitrogen (expanded nitrogen) inside the tank. Such devices have already been described. In the cabin, the subjects wore bathing suits, a pair of gloves, socks, and slippers. The subjects were instructed to turn around continuously in the cabin during the exposure period. The cryostimulation sessions were undertaken under medical supervision. The exercise physiologist administrated the intervention and the mode of administration was one-on-one.
Intervention code [1] 313702 0
Treatment: Other
Comparator / control treatment
The control group did not receive treatment (they are not exposed to cryotherapy)
Control group

Primary outcome [1] 319141 0
The number of movements during the night was used by a dimensional accelerometer
Timepoint [1] 319141 0
the whole night Following the cryotherapy exposure
Primary outcome [2] 319231 0
Subjective sleep quality was evaluated by the Spiegel questionnare
Timepoint [2] 319231 0
the next day at Morning
Secondary outcome [1] 367075 0
Heart rate variability was assessed by a heart rate monitor

Timepoint [1] 367075 0
before and immediately after cryotherapy
Secondary outcome [2] 367389 0
Skin temperature was assessed by an infrared thermometer
Timepoint [2] 367389 0
Before and immediately after cryotherapy exposure

Key inclusion criteria
Healthy ( has no chronic diseases and no diseases among those presented as a contraindication to cryotherapy) and physically active volunteers (practice more than three hours of physical activity per week).
- Professional soccer players.
Minimum age
20 Years
Maximum age
30 Years
Can healthy volunteers participate?
Key exclusion criteria
Contraindications to cryotherapy:
Hypertension, arterial disease
Myocardial infarction less than 6 months stroke pulmonary embolism
Respiratory condition (asthma, bronchopneumopathy)
Circulatory insufficiency (Raynaud's syndrome)
Angina pectoris
Pace maker or subcutaneous device
Deep vein thrombosis / phlebitis
Nephritic colic, hepatic colic
Hyperuricemia (gout attack)
Cold allergy
Cutaneous infection (acute bacterial or viral)
Acute infection
Recent intake of alcohol or drugs

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
randomised by computer
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple randomisation using a randomisation table created by computer software (i.e. computerised sequence generation)
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?

Intervention assignment
Other design features
Not Applicable
Type of endpoint(s)
Statistical methods / analysis
The required sample size was calculated from our control data concerning the number movements (counts/min) during the sleeping time using G*Power version 3.1, according to Beck ( Beck T. The importance of a priori sample size estimation in strength and conditioning research. J Strength Cond Res. 2013;27:2323-37) Using an a priori repeated-measures design with a desired power (1-beta) set at 0.80, and an alpha risk of 0.05, six subjects represent a sufficient number of subjects to detect a significant difference.The results are expressed as mean and standard deviation (SD) values or standard error when specified. The Gaussian distribution was tested for each variable using the Shapiro–Wilk test. Changes in the different variables were evaluated using repeated-measures ANOVA followed by Tukey post hoc test when appropriate. The effect size of the changes was assessed by the Hedges’ g (g) as presented by Dupuy et al (Dupuy O, Lussier M, Fraser S, Bherer L, Audiffren M, Bosquet L. Effect of overreaching on cognitive performance and related cardiac autonomic control. Scand J Med Sci Sports. 2014;24:234) and was considered to be either small (g less than 0.2 or equal to 0.5), moderate (g less than 0.5 or equal to 0.8), or large (g greater than 0.8) according to the Cohen scale (Cohen J. Statistical Power Analysis for the Behavioral Sciences. 2nd ed. Hillsdale, NJ ed.: Erlbaum; 1988.). A p<0.05 was considered to be statistically significant.

Recruitment status
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment outside Australia
Country [1] 21289 0
State/province [1] 21289 0

Funding & Sponsors
Funding source category [1] 302016 0
Self funded/Unfunded
Name [1] 302016 0
Address [1] 302016 0
Country [1] 302016 0
Primary sponsor type
University of Poitiers, faculty of sport sciences
8 ALL Jean Monnet, 86000 Poitiers
Secondary sponsor category [1] 301803 0
Name [1] 301803 0
Address [1] 301803 0
Country [1] 301803 0

Ethics approval
Ethics application status
Ethics committee name [1] 302693 0
Ethics Committee for Research in Science and Technology of Physical and Sports Activities (CERSTAPS)
Ethics committee address [1] 302693 0
University of Grenoble,
110 Avenue De La Chimie, 38400 Saint-Martin-d'Hères
Ethics committee country [1] 302693 0
Date submitted for ethics approval [1] 302693 0
Approval date [1] 302693 0
Ethics approval number [1] 302693 0

Brief summary
Objective: The aim of the present investigation was to determine whether using cryostimulation (partial-body cryostimulation) impacts sleep quality in professional soccer players.
Different exposure durations at -180°C were tested randomly after standardized training sessions in 9 professional soccer players (no cryostimulation, 180-s exposure, two 90-s exposures separated by a 5-min rest at room temperature, and 90-s exposure), and the effects on sleep quality using 3-dimensional accelerometers worn during sleep were assessed.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 91078 0
Dr Douzi Wafa
Address 91078 0
Faculté sciences du sport
Bâtiment C6
8, allée Jean Monnet TSA 31113
86073 Poitiers cedex 9
Country 91078 0
Phone 91078 0
Fax 91078 0
Email 91078 0
Contact person for public queries
Name 91079 0
Dr Douzi Wafa
Address 91079 0
Faculté sciences du sport
Bâtiment C6
8, allée Jean Monnet TSA 31113
86073 Poitiers cedex 9
Country 91079 0
Phone 91079 0
Fax 91079 0
Email 91079 0
Contact person for scientific queries
Name 91080 0
Dr Douzi Wafa
Address 91080 0
Faculté sciences du sport
Bâtiment C6
8, allée Jean Monnet TSA 31113
86073 Poitiers cedex 9
Country 91080 0
Phone 91080 0
Fax 91080 0
Email 91080 0

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No/undecided IPD sharing reason/comment
What supporting documents are/will be available?
No other documents available
Summary results
Have study results been published in a peer-reviewed journal?
Other publications
Have study results been made publicly available in another format?
Results – plain English summary
Research question: does cold exposure (cryotherapy treatment) improve the quality of sleep?
Background information : It was recently shown that cryotherapy exposure, which consists of short exposure to very cold air (from -110°C to -195°C) in special rooms (cryo chambers or cryo cabins) after exercise promotes good sleep quality both in elite athletes
Participants characteristics: Nine male football (soccer) professional players (24.8 ± 5.5 years; 76.7 ± 7.3 kg; 184 ± 0.1 cm) from the Niort Football Club (French National Championship Ligue 2) participated in the study
Key results: The number of movements during the night after partial-body cryostimulation was significantly reduced only in the 180-s exposure condition (very large effect size) compared with the control condition. Partial-body cryostimulation seems to induce a positive impact on sleep quality that may be dose-dependent.
Limitations: This work is a small scale trial and should be completed to assure that sleep quality is improved by using partial-body cryostimulation in athletes after physical exercise.