Ralph F. Goldman

Differentiated Ratings of Perceived Exertion during Physical Conditioning of Older Individuals Using Leg-Weight Loading:

Use of leg weights for physical conditioning was evaluated in 8 middle-aged male Ss; four Ss of similar age served as a control group. Pre- and post-training evaluation consisted of heart rate and oxygen uptake responses to five submaximal work loads which involved either level walking or cycling. Differentiated ratings of perceived exertion elicited for each work load were: a local muscular rating; a central or cardio-pulmonary rating; and an over-all or general rating. Submaximal heart rate decreased 6 to 9 beats/min. from pretraining values for all work loads after training. The differentiated ratings for training generally reflected a reduced strain on the cardiovascular system and also the improved functioning of the working muscles with training. However, when one set of sensations dominated the exertional perception the others appear to have been perceptually de-emphasized. Local muscular factors seemed to dominate the exertional perception for cycling, but central factors appeared to play a more important role for treadmill walking, at least within the range of velocities investigated.

The effect of diet on thermogenesis in acquired lipodystrophy.

Abstract We tested the effect of variation of intake of carbohydrate, fat, protein, and total calories on the metabolic rate and thyroid hormones in an 18-yr-old female with total acquired lipodystrophy and a 23-yr-old normal female control subject. The lipodystrophic subjects resting metabolic rates, when expressed as W/m 2 body surface area, were elevated and varied directly with the caloric intake. The metabolic rates were highest after 3 days of the protein-supplemented diet and lowest after a 3 day fast. Serum triiodothyronine (T 3 ) concentrations of the lipodystrophic subject were within the normal range but varied directly with the caloric content of the diet. T 3 was highest during the period of protein supplementation and lowest after the 3 day fast. The resting metabolic rate rose beyond the normal range in the control subject only after 3 days of the protein-supplemented diet and fell to low normal values after the 3 day fast. In contrast to the finding in the lipodystrophic subject, T 3 concentrations were stable after each 3–6 day dietary alteration. We conclude that there is relative metabolic lability in the lipodystrophic subject, and this may be related to the diminished capacity to store energy as fat. Metabolic rates, when calculated as W/kg estimated lean mass, were normal in the lipodystrophic subject, consuming reduced amounts of food (1800 cal/day). The role, if any, of T 3 in modulating these processes is unclear. The subject with lipodystrophy may demonstrate a form of dietary-induced thermogenesis.

METHODS FOR EVALUATION OF LOAD-CARRIAGE SYSTEMS

In an effort to evaluate the effectiveness of a new load-carriage system on man, energy cost studies were done comparing the new system with a standard load-carriage system. Three different methods of treadmill walking were used for the comparison: (1) investigator controlled treadmill speed, (2) subject controlled treadmill speed, and (3) heart-rate controlled treadmill speed. Although none is entirely new, these three approaches provide practical means to measure the cost of work. Since there were no statistically significant differences between the two load-carriage systems, it was concluded that as long as weight is properly distributed over the body, weight per se is the most important factor in load carriage rather than the specific load-carriage system design.

Physical Conditioning of Sedentary Young Men with Ankle Weights during Working Hours

An intact work crew of nine weather observers (ages 19-32 y) wore weighted ankle spats for 20 continuous days for 7·5-7·9 h each day on the job while performing normal duties and for an equal amount of time on days off. Four observers continued wear for another 20 days. Weights on each ankle were 2·25 kg for two days and 3·0 kg thereafter. Oxygen uptake (V˙O2) and heart rate (HR) were determined before and after conditioning at six submaximal work loads: level walking at 1·12 and 1·56ms−1, with and without ankle weights, and crgometer cycling at two work loads selected to elicit final HR near 150 and 180 beat min−1. Submaximal HR declined and predicted aerobic power at HR = 180 (PAP180) increased throughout the conditioning period, but significance was reached only after six weeks (mean HR decrease = 18 beat min−1, p<0·05; mean PAP180 increase = 0·15 mmolmin−1 kg−1, p<0·05). After three weeks without weights, both improvements partially decayed. V˙O2 and HR were obtained on the job from three subjects who...

Pacing of intermittent work during 31 hours.

ABSTRACTSubjects walked one hour out of every six on a self-paced treadmill, during two separate 31 hour test periods, carrying either a 15 or 30 kg pack. During the 31 hour period each subject walked for 6 one hour periods (or walked 4.8 km each period) without sleep during the intervening five hou