PHYSICAL PERFORMANCE AND METABOLIC RECOVERY AMONG LEAN, HEALTHY-MEN FOLLOWING A PROLONGED ENERGY DEFICIT

Previous studies have demonstrated that full recovery from weight loss may take months or years. The present investigation examined short-te rm recovery (5 wks ''post'') of physical performance (muscular strengt h, muscular power, vertical jump), body composition, metabolic hormone s (testosterone, luteinizing hormone, sex hormone binding globulin, in sulin-like growth factor-1, triiodothyronine, thyroxine, thyroid bindi ng globulin, and thyroid-stimulating hormone) and metabolic markers (t ransferrin, ferritin, prealbumin, glycerol, nonesterified fatty acids, high-density lipoproteins, and lactate) in 10 healthy young men after an 8-week Army course with an energy deficit (1000 kcal/d) and loss o f body mass (-12%). Subjects ate ad libitum after the course ended ('' post''). Body composition was determined by dual-energy X-ray absorpti ometry; strength from a simulated power clean, power from body mass an d jump height, and metabolic hormones were measured in morning-fasted blood by radioimmunoassay. With the exception of transferrin and glyce rol, all study parameters were significantly (p < .05) altered by the training course. At 5 weeks post fat-free mass along with all physical performance measures returned to initial levels; however, fat mass ha d significantly (p < .05) increased over initial levels. Also, with th e exception of lactate, all measured hormones and markers were close t o initial levels and within normal ranges. Reported complications duri ng recovery included sleep irregularities, diarrhea, loss of motivatio n and feelings of fatigue. While the long range effect of this energy deprivation experience is uncertain, these data do suggest that severe weight loss does not result in lasting alterations of the contractile and metabolic properties of skeletal muscle in young, lean, healthy m en.