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

Inland Norway University of Applied Sciences18 enrolled

Overview

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

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

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

NONE

Enrollment

Conditions

Healthy Cyclists

Interventions

Inclusion of sprints during low-intensity cycling during a 14-day training camp (high training load)BEHAVIORAL

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.

Low-intensity cycling during a 14-day training camp (high training load)BEHAVIORAL

Five low-intensity cycling sessions (\>four hours per session), distance-matched to sprint group.

Recovery for 10 days (low training load)

Eligibility

Sex: MALEMin age: 18 YearsMax age: 40 YearsHealthy volunteers:

Medical Language ↔ Plain English

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

Locations (1)

Inland Norway University of Applied Sciences

Lillehammer, Norway

Outcomes

Primary Outcomes

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

Time frame: Changes from before the intervention (T0) to immediately after the intervention (T2, after REC)

Secondary Outcomes

Sprint performance

Mean power output measured during four consecutive 30-s maximal sprints

Time frame: 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

Time frame: 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

Time frame: 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)

Time frame: 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)

Time frame: Changes from before the intervention (T0) to immediately after the intervention (T2, i.e. after REC)

Data from ClinicalTrials.gov

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Habitual low-intensity cycling (\>0.5-2 hours per session)

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)

Time frame: 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)

Time frame: 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)

Time frame: 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

Time frame: 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

Time frame: Changes from before the intervention (T0) to immediately after the training camp (T1)

Haemoglobin mass (training camp)

Hemoglobin mass measured using CO rebreathing (g)

Time frame: Changes from before the intervention (T0) to immediately after the training camp (T1)

Haemoglobin mass (recovery/REC)

Hemoglobin mass measured using CO rebreathing (g)

Time frame: 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

Time frame: Changes from before the intervention (T0) to immediately after the training camp (T1)

Blood volume (recovery/REC)

Blood volume measured using CO rebreathing

Time frame: 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

Time frame: Changes from before the intervention (T0) to immediately after the training camp (T1)

Plasma volume (recovery/REC)

Plasma volume measured using CO rebreathing

Time frame: 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

Time frame: 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

Time frame: 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

Time frame: 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

Time frame: Changes from before the intervention (T0) to immediately after the intervention (T2, i.e. after REC)

Hematocrit (training camp)

Hematocrit measured using centrifugation

Time frame: Changes from before the intervention (T0) to immediately after the training camp (T1)

Hematocrit (recovery/REC)

Hematocrit measured using centrifugation

Time frame: 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

Time frame: 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

Time frame: 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)

Time frame: 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

Time frame: 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

Time frame: 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

Time frame: 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

Time frame: 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)

Time frame: 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)

Time frame: 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)

Time frame: Changes from before the intervention (T0) to immediately after the intervention (T2, i.e. after REC)