Outcome
Type |
Measure |
Description |
Time frame |
Safety issue |
Primary |
Endurance performance I |
Change of maximal oxygen uptake (VO2max in ml/min/kg) compared to baseline and group |
10 to 21 days (assessment is conducted once before the intervention and repeated three times afterwards, i.e. 3, 7 and 14 days after the completion of the intervention) |
|
Primary |
Endurance performance II |
Change of peak performance (Ppeak in Watt) compared to baseline and group |
10 to 21 days (assessment is conducted once before the intervention and repeated three times afterwards, i.e. 3, 7 and 14 days after the completion of the intervention) |
|
Primary |
Endurance performance III |
Change of 5 kilometer time trial performance (in sec) compared to baseline and group |
20 to 22 days (the assessment is conducted once before, and once after the intervention) |
|
Primary |
Endurance performance IV |
Change of lactate threshold (in km/h) compared to baseline and group |
10 to 21 days (assessment is conducted once before the intervention and repeated three times afterwards, i.e. 3, 7 and 14 days after the completion of the intervention) |
|
Primary |
Endurance performance V |
Change of ventilatory thresholds (in km/h) compared to baseline and group |
10 to 21 days (assessment is conducted once before the intervention and repeated three times afterwards, i.e. 3, 7 and 14 days after the completion of the intervention) |
|
Primary |
Endurance performance VI |
Change of running economy (in ml/min/kg) compared to baseline and group |
10 to 21 days (assessment is conducted once before the intervention and repeated three times afterwards, i.e. 3, 7 and 14 days after the completion of the intervention) |
|
Secondary |
Change of questionnaire scores - well-being |
Change of questionnaire scores compared to baseline and group as determined by a Visual-Analogue-Scale (from 0-100 millimeters). Higher scores indicate poorer well-being. |
30 days (questionnaires will be given to participants several times before, during, and after the intervention.) |
|
Secondary |
Change of questionnaire scores - muscular fatigue |
Change of questionnaire scores compared to baseline and group as determined by a Visual-Analogue-Scale (from 0-100 millimeters). Higher scores indicate higher degree of fatigue. |
30 days (questionnaires will be given to participants several times before, during, and after the intervention.) |
|
Secondary |
Change of questionnaire scores - vitality |
Change of questionnaire scores compared to baseline and group as determined by a Likert-Scale (from 0-10). Higher scores indicate higher vitality. |
30 days (questionnaires will be given to participants several times before, during, and after the intervention.) |
|
Secondary |
Change of questionnaire scores - rate of fatigue |
Change of questionnaire scores compared to baseline and group as determined by a Likert-Scale (from 0-10). Higher scores indicate higher degree of fatigue. |
30 days (questionnaires will be given to participants several times before, during, and after the intervention.) |
|
Secondary |
Change of questionnaire scores - sleep quality |
Change of questionnaire scores compared to baseline and group as determined by a Likert-Scale (from 1-7). Higher scores indicate poorer sleep. |
30 days (questionnaires will be given to participants several times before, during, and after the intervention.) |
|
Secondary |
Change of blood count |
Change of blood count concentrations compared to baseline and group |
30 days (blood is drawn from participants several times before, during, and after the intervention.) |
|
Secondary |
Change of cell-free DNA |
Change of cell-free DNA concentrations compared to baseline and group |
30 days (blood is drawn from participants several times before, during, and after the intervention.) |
|
Secondary |
Change of creatine kinase |
Change of creatine kinase concentrations compared to baseline and group |
30 days (blood is drawn from participants several times before, during, and after the intervention.) |
|
Secondary |
Change of urea |
Change of urea concentrations compared to baseline and group |
30 days (blood is drawn from participants several times before, during, and after the intervention.) |
|
Secondary |
Change of blood lactate |
Change of blood lactate concentrations compared to baseline and group |
30 days (blood is drawn from participants several times before, during, and after the intervention.) |
|
Secondary |
Change of cytokines |
Change of cytokine concentrations compared to baseline and group |
30 days (blood is drawn from participants several times before, during, and after the intervention.) |
|
Secondary |
Change of miRNA |
Change of miRNA compared to baseline and group |
30 days (blood is drawn from participants several times before, during, and after the intervention.) |
|
Secondary |
Change of neuromuscular performance |
Change of neuromuscular performance (counter movement jump height in cm) measured on a contact plate (AMTI, Watertown, USA) compared to baseline and group |
30 days (neuromuscular performance is assessed several times before, during, and after the intervention) |
|
Secondary |
Change of body weight |
Change of body weight in kg compared to baseline and group |
10 to 21 days (assessment is conducted once before the intervention and repeated three times afterwards, i.e. 3, 7 and 14 days after the completion of the intervention) |
|
Secondary |
Change of fat free mass |
Change of fat free mass in kg compared to baseline and group |
10 to 21 days (assessment is conducted once before the intervention and repeated three times afterwards, i.e. 3, 7 and 14 days after the completion of the intervention) |
|
Secondary |
Change of fat mass |
Change of fat mass in kg compared to baseline and group |
10 to 21 days (assessment is conducted once before the intervention and repeated three times afterwards, i.e. 3, 7 and 14 days after the completion of the intervention) |
|
Secondary |
Change of forced expiratory volume |
Change of forced expiratory volume in liters compared to baseline and group |
10 to 21 days (assessment is conducted once before the intervention and repeated three times afterwards, i.e. 3, 7 and 14 days after the completion of the intervention) |
|
Secondary |
Change of power output during exercise |
Change of power output in Watt (as determined via Stryd, Boulder, USA) during the intervention compared to baseline and group |
7 days |
|
Secondary |
Change of sleep quality I - GPS watch |
Change of sleep quality compared to baseline and group as determined by a GPS (Global Positioning System) watch |
30 days (sleep is assessed several times before, during, and after the intervention) |
|
Secondary |
Change of sleep quality II - ABIOS App |
Change of sleep quality compared to baseline and group as determined by the ABIOS (Algorithmik Biodata System) application |
30 days (sleep is assessed several times before, during, and after the intervention) |
|
Secondary |
Correlations between sleep quality devices |
To determine the correlations between different sleep monitoring devices, i.e. the GPS watch (see outcome 27), the ABIOS system (see outcome 28) and the sleep quality questionnaire (see outcome 11) |
30 days |
|
Secondary |
Change of parameters recorded by an electrocardiogram - mean heart rate |
Change of mean heart rate compared to baseline and group |
30 days (an electrocardiogram is written several times before, during, and after the intervention) |
|
Secondary |
Change of parameters recorded by an electrocardiogram - heart rate variability |
Change of heart rate variability (root mean sum of squared distance in ms) compared to baseline and group |
30 days (an electrocardiogram is written several times before, during, and after the intervention) |
|
Secondary |
Change of executive functions - Eriksen flanker task |
Change of executive functions compared to baseline and group. This is recorded through a modified Eriksen flanker task consisting of 108 images showing five white arrows on a black screen. |
30 days (executive functions are tested several times before, during, and after the intervention) |
|
Secondary |
Change of executive functions - 2 back task |
Change of executive functions compared to baseline and group. This is assessed through a 2-back task showing dots on a dice, numbers and geometrical figures. |
30 days (executive functions are tested several times before, during, and after the intervention) |
|
Secondary |
Cardiac ultrasound |
Description of an athlete cohort regarding cardiac chamber volume (in ml, determined via EPIQ CVX, X5-1, Philips Healthcare, Andover, MA, USA) |
1 day (this outcome will be determined once before study start) |
|
Secondary |
Adherence to training program |
Adherence to the HIIT training programs (determined as the ratio of training sessions performed to prescribed training sessions). This is determined by the researchers by checking the training data of the athletes. For example, if 9 out of 10 sessions were performed, this means 90% adherence. |
7 days |
|