Effects of Including Sprints During Low-intensity Cycling Exercises on Performance and Muscle/Blood Characteristics

Study Overview
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Brief Summary
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To investigate the effects of Including 30-s sprints during low-intensity cycling exercises during a training camp on performance and muscle/blood characterisitcs in elite cyclists

Detailed Description
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Inclusion of sprint intervals during low-intensity training (LIT) sessions has been suggested as a potential mean to improve endurance performance in elite cyclists, facilitated by muscular or systemic physiological adaptations. So far, the effects of such training has been studied exclusively in context of short-lasting low-intensity sessions, representing a scenario with suboptimal ecological validity for such highly trained athetes. This study will investigate the effects of including sprints during prolonged LIT-sessions sessions during a 14-day training camp focusing on LIT, followed by 10 days recovery (REC), on performance and performance-related measures in elite cyclists. During the training camp, a sprint training group will conduct 12x30-s maximal sprints during five LIT sessions, whereas a control group will perform distance-matched LIT-only. Overall, the training camp will lead to substantial increases in training load compared to habitual training in both intervention groups, followed by subsequent reductions during REC. Performance tests will be conducted before the training camp (T0) and after REC (T2). Muscle biopsies, hematological measures and stress/recovery questionnaires will be collected Pre (T0) and after the camp (T1). The study was pre-registered at Norwegian Center for Research Data (14/08/2017, Norwegian): http://pvo.nsd.no/prosjekt/55322

Official Title
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Effects of Including 30-s Sprints During Low-intensity Cycling Exercises During a Training Camp on Performance and Muscle/Blood Characterisitcs

Conditions
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Healthy, Cyclists

Intervention / Treatment
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* Behavioral: Inclusion of sprints during low-intensity cycling during a 14-day training camp (high training load)
* Behavioral: Low-intensity cycling during a 14-day training camp (high training load)
* Behavioral: Recovery for 10 days (low training load)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: VO2max > 65ml/kg/min Exclusion Criteria: VO2max < 65ml/kg/min Average endurance training per week >10hrs/wk during the four weeks leading up to the study

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 40 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Investigating the effects of including sprints during low-intensity training sessions during a 14-d training camp with increased training load on performance and muscle/blood biology
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Sprints during low-intensity cycling<br> | Behavioral: Inclusion of sprints during low-intensity cycling during a 14-day training camp (high training load)<br>* Inclusion of 12x30-s maximal sprints during five low-intensity cycling sessions with long duration (>fours hours per session). Five sessions will be performed as low-intensity cycling-only (Controll sessions, distance matched). All other sessions will be performed as low-intensity sessions and adjusted according to each participants training load goal to reach an increase of  50% in load compared to habitual training.<br>Behavioral: Recovery for 10 days (low training load)<br>* Habitual low-intensity cycling (>0.5-2 hours per session)<br>|
| Active Comparator: Low-intensity cycling<br> | Behavioral: Low-intensity cycling during a 14-day training camp (high training load)<br>* Five low-intensity cycling sessions (>four hours per session), distance-matched to sprint group.<br>Behavioral: Recovery for 10 days (low training load)<br>* Habitual low-intensity cycling (>0.5-2 hours per session)<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Performance during a 5-minute all-out cycling test | Mean power output measured during a 5-minute all-out cycling test performed at the end of a  2 hour long exercise protocol | Changes from before the intervention (T0) to immediately after the intervention (T2, after REC) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Sprint performance | Mean power output measured during four consecutive 30-s maximal sprints | Changes from before the intervention (T0) to immediately after the intervention (T2, after REC) | 
| Maximal oxygen uptake | Maximal oxygen consumption measured during an incremental cycling exercise test to exhaustion | Changes from before the intervention (T0) to immediately after the intervention (T2, i.e. after REC) | 
| Maximal aerobic power output | Maximal aerobic power output measured as mean power output during the last minute of an incremental cycling exercise test to exhaustion | Changes from before the intervention (T0) to immediately after the intervention (T2, i.e. after REC) | 
| Gross efficiency (training camp) | Contribution of total energy turnover to power output in the fresh and fatigued state incremental cycling exercise test (with 5 minute steps) | Changes from before the intervention (T0) to immediately after the training camp (T1) | 
| Gross efficiency (recovery/REC) | Contribution of total energy turnover to power output in the fresh and fatigued state incremental cycling exercise test (with 5 minute steps) | Changes from before the intervention (T0) to immediately after the intervention (T2, i.e. after REC) | 
| Power output at lactate threshold (training camp) | Power output at 4 mmol blood lactate concentration measured during an incremental cycling exercise test (with 5 minute steps) | Changes from before the intervention (T0) to immediately after the training camp (T1) | 
| Power output at lactate threshold (recovery/REC) | Power output at 4 mmol blood lactate concentration measured during an incremental cycling exercise test (with 5 minute steps) | Changes from before the intervention (T0) to immediately after the intervention (T2, i.e. after REC) | 
| Fractional utilization of VO2max (incremental test) | Fractional utilization of VO2max measured at 4 mmol blood lactate concentrations measured during an incremental cycling exercise test (with 5 minute steps) | Changes from before the intervention (T0) to immediately after the intervention (T2, i.e. after REC) | 
| Fractional utilization of VO2max (5-min test) | Fractional utilization of VO2max measured during the 5-min test | Changes from before the intervention (T0) to immediately after the intervention (T2, i.e. after REC) | 
| Protein abundance in skeletal muscle | Protein abundances in m. vastus lateralis measured using western blotting | Changes from before the intervention (T0) to immediately after the training camp (T1) | 
| Haemoglobin mass (training camp) | Hemoglobin mass measured using CO rebreathing (g) | Changes from before the intervention (T0) to immediately after the training camp (T1) | 
| Haemoglobin mass (recovery/REC) | Hemoglobin mass measured using CO rebreathing (g) | Changes from before the intervention (T0) to immediately after the intervention (T2, i.e. after REC) | 
| Blood volume (training camp) | Blood volume measured using CO rebreathing | Changes from before the intervention (T0) to immediately after the training camp (T1) | 
| Blood volume (recovery/REC) | Blood volume measured using CO rebreathing | Changes from before the intervention (T0) to immediately after the intervention (T2, i.e. after REC) | 
| Plasma volume (training camp) | Plasma volume measured using CO rebreathing | Changes from before the intervention (T0) to immediately after the training camp (T1) | 
| Plasma volume (recovery/REC) | Plasma volume measured using CO rebreathing | Changes from before the intervention (T0) to immediately after the intervention (T2, i.e. after REC) | 
| Red blood cell volume (training camp) | Red blood cell volume measured using CO rebreathing | Changes from before the intervention (T0) to immediately after the training camp (T1) | 
| Red blood cell volume (recovery/REC) | Red blood cell volume measured using CO rebreathing | Changes from before the intervention (T0) to immediately after the intervention (T2, i.e. after REC) | 
| Mean corposcular volume (training camp) | Mean corposcular volume measured using CO rebreathing | Changes from before the intervention (T0) to immediately after the training camp (T1) | 
| Mean corposcular volume (recovery/REC) | Mean corposcular volume measured using CO rebreathing | Changes from before the intervention (T0) to immediately after the intervention (T2, i.e. after REC) | 
| Hematocrit (training camp) | Hematocrit measured using centrifugation | Changes from before the intervention (T0) to immediately after the training camp (T1) | 
| Hematocrit (recovery/REC) | Hematocrit measured using centrifugation | Changes from before the intervention (T0) to immediately after the intervention (T2, i.e. after REC) | 
| Body mass (training camp) | Body mass (kg) measured using Dual-energy X-ray absorptiometry | Changes from before the intervention (T0) to immediately after the training camp (T1) | 
| Body mass (recovery/REC) | Body mass (kg) measured using Dual-energy X-ray absorptiometry | Changes from before the intervention (T0) to immediately after the intervention (T2, i.e. after REC) | 
| Enzyme activity in skeletal muscle | Enzyme activity in m. vastus lateralis measured using ELISA kits (I.e., CS and PFK) | Changes from before the intervention (T0) to immediately after the training camp (T1) | 
| Lean body mass (training camp) | Lean body mass (kg) measured using Dual-energy X-ray absorptiometry | Changes from before the intervention (T0) to immediately after the training camp (T1) | 
| Lean body mass (recovery/REC) | Lean body mass (kg) measured using Dual-energy X-ray absorptiometry | Changes from before the intervention (T0) to immediately after the intervention (T2, i.e. after REC) | 
| Fat mass (training camp) | Fat mass (kg) measured using Dual-energy X-ray absorptiometry | Changes from before the intervention (T0) to immediately after the training camp (T1) | 
| Fat mass (recovery/REC) | Fat mass (kg) measured using Dual-energy X-ray absorptiometry | Changes from before the intervention (T0) to immediately after the intervention (T2, i.e. after REC) | 
| Session rate of percieved exertion | Session rate of percieved exertion (sRPE) measured after each exercise involving sprints/control exercise using a 9-point scale ranging from very, very demotivated to very, very motivated (1 to 9) | Throughout the training camp (14 days) | 
| Stress-recovery state (training camp) | Recovery state of participants measured using Recovery-Stress Questionnaire for Athletes (RESTQ-36-R-Sport, 36 questions, 7-point scale ranging from 0/never to 6/always) | Changes from before the intervention (T0) to immediately after the training camp (T1) | 
| Stress-recovery state (recovery/REC) | Recovery state of participants measured using Recovery-Stress Questionnaire for Athletes (RESTQ-36-R-Sport, 36 questions, 7-point scale ranging from 0/never to 6/always) | Changes from before the intervention (T0) to immediately after the intervention (T2, i.e. after REC) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Sprint, Low-intensity cycling, Skeletal muscle, Endurance performance