Supplemental Protein during Heavy Cycling Training and Recovery Impacts Skeletal Muscle and Heart Rate Responses but Not Performance.
The effects of protein supplementation on cycling performance, skeletal muscle function, and heart rate responses to exercise were examined following intensified (ICT) and reduced-volume training (RVT). Seven cyclists performed consecutive periods of normal training (NT), ICT (10 days; average training duration 220% of NT), and RVT (10 days; training duration 66% of NT). In a crossover design, subjects consumed supplemental carbohydrate (CHO) or an equal amount of carbohydrate with added protein (CP) during and following each exercise session (CP = +0.94 g/kg/day protein during ICT; +0.39 g/kg/day during RVT). A 30-kilometer time trial performance (following 120 min at 50% Wmax) was modestly impaired following ICT (+2.4 ± 6.4% versus NT) and returned to baseline levels following RVT (-0.7 ± 4.5% versus NT), with similar responses between CHO and CP. Skeletal muscle torque at 120 deg/s benefited from CP, compared to CHO, following ICT. However, this effect was no longer present at RVT. Following ICT, muscle fiber cross-sectional area was increased with CP, while there were no clear changes with CHO. Reductions in constant-load heart rates (at 50% Wmax) following RVT were likely greater with CP than CHO (-9 ± 9 bpm). Overall it appears that CP supplementation impacted skeletal muscle and heart rate responses during a period of heavy training and recovery, but this did not result in meaningful changes in time trial performance.
Department of Kinesiology, James Madison University, 261 Bluestone Drive MSC 2302, Harrisonburg, VA 22807, USA. dlugosac@dukes.jmu.edu.
Andrew C
AC
D'Lugos
Department of Kinesiology, James Madison University, 261 Bluestone Drive MSC 2302, Harrisonburg, VA 22807, USA. ludennd@jmu.edu.
Nicholas D
ND
Luden
Department of Kinesiology, James Madison University, 261 Bluestone Drive MSC 2302, Harrisonburg, VA 22807, USA. fallerjm@dukes.jmu.edu.
Justin M
JM
Faller
Department of Kinesiology, James Madison University, 261 Bluestone Drive MSC 2302, Harrisonburg, VA 22807, USA. akersjd@jmu.edu.
Jeremy D
JD
Akers
Department of Kinesiology, James Madison University, 261 Bluestone Drive MSC 2302, Harrisonburg, VA 22807, USA. mckenzai@dukes.jmu.edu.
Alec I
AI
McKenzie
Department of Kinesiology, James Madison University, 261 Bluestone Drive MSC 2302, Harrisonburg, VA 22807, USA. saundemj@jmu.edu.
Michael J
MJ
Saunders
D000293:Adolescent; D000328:Adult; D054874:Athletic Performance; D001642:Bicycling / Q000502:physiology*; D015415:Biomarkers / Q000097:blood; D001835:Body Weight; D003402:Creatine Kinase / Q000097:blood; D018592:Cross-Over Studies; D004040:Dietary Carbohydrates / Q000008:administration & dosage / Q000032:analysis; D004041:Dietary Fats / Q000008:administration & dosage / Q000032:analysis; D004044:Dietary Proteins / Q000008:administration & dosage*; D019587:Dietary Supplements; D004311:Double-Blind Method; D002149:Energy Intake; D015444:Exercise / Q000502:physiology; D005260:Female; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D008297:Male; D018485:Muscle Fibers, Skeletal / Q000187:drug effects* / Q000378:metabolism; D063806:Myalgia / Q000188:drug therapy; D010101:Oxygen Consumption; D010807:Physical Endurance; D012709:Serum Albumin / Q000378:metabolism; D064133:Sports Nutritional Physiological Phenomena; D055815:Young Adult
D015415:Biomarkers; D004040:Dietary Carbohydrates; D004041:Dietary Fats; D004044:Dietary Proteins; D012709:Serum Albumin; D003402:Creatine Kinase; D006854:Hydrocortisone
carbohydrate; chocolate milk; muscle repair; protein; sports nutrition