LOWER BODY NEGATIVE PRESSURE EXERCISE AS A TRAINING MODALITY

BIOMECHANICAL AND PHYSIOLOGICAL RESPONSES

INTRODUCTION:

Lower body negative pressure exercise (LBNP) is a concept recently introduced for maintaining astronaut exercise and fitness during extended stays in microgravity. An additional application may be for athletic training. LBNP increases musculoskeletal and cardiovascular loads. The purpose of this study was to evaluate gait mechanics and cardiovascular responses to LBNP as a vigorous training modality.

METHODS:

Six subjects were tested at 100%, 110% and 120% bodyweights (BW) while treadmill running at 2.5 m/s for 3 minutes in a transparent LBNP chamber, with at least 15 minutes rest between bouts. These data were collected continuously: heart rate (HR), oxygen consumption (VO2), knee range of motion (ROM), vertical ground reaction force (GRF) and surface EMG of tibialis anterior (TA), medial gastrocnemius (MG), vastus medialis obliquous (VMO) and biceps femoris (BF). Data were analyzed by one-way repeated measures ANOVA with Bonferroni post-hoc comparisons (p < .05).

RESULTS:

Heart rate increased more under LBNP conditions than at normal BW (p < .01), in some cases up to 180 beats per minute within 2–3 minutes of running at 1.2 BW. There was a trend toward increased peak VO2 (p = .11) and increased GRF (p = .07) with LBNP. Knee ROM and EMG activation patterns did not change significantly during LBNP running.

CONCLUSION:

Previous vigorous training modalities have included running uphill or carrying extra weight. However, these training strategies alter gait mechanics and may increase susceptibility to injury. Our data suggest that LBNP increases cardiovascular response without altering gait mechanics and muscle activation patterns. LBNP may be an efficient technique for increasing cardiovascular performance in recreational and elite athletes. Supported by Bristol Myers/Zimmer Center of Excellence, UCSD Chancellor's Associates