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Neuroendocrine Responses to an Acute Bout of Eccentric-Enhanced Resistance Exercise


Medicine & Science in Sports & Exercise: June 2007 - Volume 39 - Issue 6 - p 941-947
doi: 10.1097/mss.0b013e318043a249
BASIC SCIENCES: Original Investigations

Purpose: The purpose of this study was to compare the total testosterone (TT), bioavailable testosterone (BT), growth hormone (GH), lactate, and ratings of perceived exertion (RPE) responses between a single bout of traditional (TRAD) and eccentric-enhanced resistance exercise (ECC+) of matched training volumes.

Methods: Twenty-two previously untrained males (21.9 ± 0.8 yr) completed one familiarization and one baseline 1RM testing bout, for the bench press and squat exercises, and then two exercise bouts. During exercise bout 1, all subjects completed a TRAD protocol (four sets of six reps at 52.5% 1RM), and the subsequent exercise bout consisted of either a TRAD or an ECC+ protocol (three sets of six reps at 40% 1RM concentric and 100% 1RM eccentric) for the bench press and squat exercises. Blood samples acquired at rest, immediately after (T 1), and 15, 30, 45, and 60 min after exercise were assessed for serum TT, BT, GH, and blood lactate concentrations.

Results: Resting and postexercise TT, BT, and GH were not significantly different between groups. Postexercise TT was not elevated during either bout or in either group, whereas BT increased 15-16% at T 1 in both groups during bout 2. Postexercise GH concentrations were elevated 500-7000% above baseline after both protocols. Postexercise lactate accumulation and RPE were greater with ECC+ than TRAD.

Conclusion: TRAD and ECC+ show similar neuroendocrine and differing metabolic responses during the early phase of resistance exercise in untrained, college-age men.

1University of Florida, Department of Applied Physiology & Kinesiology, Center for Exercise Science, Gainesville, FL; 2Geriatric Research Education and Clinical Center, VA Medical Center, Gainesville, FL; 3University of Florida, Food Science and Human Nutrition Department, Gainesville, FL; and 4University of Florida College of Medicine, Department of Physiology and Functional Genomics, Gainesville, FL

Address for correspondence: Joshua F. Yarrow, Ph.D., University of Florida, 25 Florida Gym, Gainesville, FL 32611-8206; E-mail:

Submitted for publication October 2006.

Accepted for publication February 2007.

©2007The American College of Sports Medicine