Maximal manual stretcher carriage: performance and recovery of male and female ambulance workers.
The effects of a maximal duration stretcher carriage on heart rate (HR), lactate concentration, hand steadiness and hand-grip strength were studied up to 72 h post-exercise in 17 male and 15 female military ambulance personnel. Using both hands for transport, the participants walked on a treadmill ergometer at a speed of 4.5 km/h. Force measurements at the handlebars yielded mean loads of 245 N (25 kg) on each side. Each step on the treadmill induced additional force oscillations with peak forces up to 470 N corresponding to 130% (women) and 98% (men) of maximal voluntary contraction (MVC). In the males the maximal transport time was about twice the time in women (mean +/- SD: 184 +/- 51 s vs. 98 +/- 34 s). These differences had no significant effect on HR and lactate values. The same applies to hand steadiness, which showed only a transient deterioration immediately after exercise. In contrast to these parameters, substantial differences were seen in hand-grip strength recovery. Immediately after exercise, maximal hand-grip strength decreased by 150 N (25% MVC) in the males vs. 50 N (14%) in the females. Irrespective of gender, individuals with larger hand-grip strength and longer carriage durations (range 120 s-280 s) showed the slowest strength recoveries (up to 72 h) as compared to 1 h of recovery in participants with short transport durations (range 27 s-120 s). These findings suggest that the increasing number of eccentric strains during uninterrupted stretcher carriage induces cumulative muscle damages that may require some days for complete recovery.
Leyk
D
D
Department IV-Military Ergonomics and Exercise Physiology, Central Institute of the Federal Armed Forces Medical Services Koblenz, Koblenz, Germany. Leyk@dshs-koeln.de
Rohde
U
U
Erley
O
O
Gorges
W
W
Essfeld
D
D
Erren
T C
TC
Piekarski
C
C
D000222:Adaptation, Physiological; D000293:Adolescent; D000328:Adult; D000552:Ambulances; D001696:Biomechanical Phenomena; D004634:Emergency Medical Technicians; D005080:Exercise Test; D005221:Fatigue / Q000503:physiopathology*; D005260:Female; D018737:Hand Strength / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008889:Military Personnel; D013995:Time; D016474:Weight-Bearing / Q000502:physiology*