"As shown by other studies, when breathing muscles become fatigued, the body switches to survival mode and "steals" blood flow and oxygen away from the locomotor muscles and redirects it to the respiratory muscles to enable the diver to continue breathing. Deprived of oxygen and fuel, the locomotor muscles become fatigued.
"Increasing the strength and endurance of the respiratory muscles prevents their fatigue during sustained exercise, enabling divers and swimmers to sustain their effort longer without tiring," Lundgren said.
The study involved 30 experienced male swimmers in their 20s. To insure the safety of participants and establish uniform fitness, all enrollees took four weeks of swim-fin and scuba-diving training before the start of the study.
Participants also underwent baseline tests to determine pulmonary strength (maximal pressures they could generate), pulmonary endurance (time that a high ventilation could be sustained), VO2max (the maximal volume of oxygen they could consume per minute to produce energy for exercise), and length of time they could swim at a moderately high speed.
The men then were randomized to one of three training protocols: RRMT-resistance respiratory muscle training; ERMT-endurance respiratory muscle training; or PRMT-placebo respiratory muscle training. The protocols were followed for 30 minutes per day, five days a week, for four weeks.
Swimmers assigned to the RRMT inhaled and exhaled against a valve that had a set opening pressure and imposed a continuous resistance using specialized breathing valves and a computer tracking system developed in CRESE.
Swimmers in the ERMT protocol, using the same equipment, increased their breathing rate and tidal volume (total ventilation) progressively each week, while a re-breathing bag insured that the a
Contact: Lois Baker
University at Buffalo