The main purpose was to test the hypothesis that the true force and power in weightlifting were related significantly to the strengthening stimulus. Secondary hypotheses were (a) slower, heavier weight training for strength would increase strength, not maximum power, (b) faster, lighter weight training for maximum power would increase maximum power, not strength and (c) there would be no significant difference between force = mass (F = m) and true force = mass multiplied by acceleration (F = ma) for arm weightlifting. Using an optical encoder, digital recorder and a data-logging computer on an arm weightlifting machine, F = m and F = ma were significantly different between 25% and 94%, contrary to published reports, but not at 100% of strength. A second-order polynomial equation predicted force, F = ma, as a multiple of the weight lifted, from the velocity of the lift with R2 = 0.997. A group was trained for strength and a matched group was trained for maximum power. The strength group gained significantly in maximum power and the power group gained significantly in strength and maximum power. Both groups gained significantly in velocity, but not force, at maximum power. The correlations between strength and maximum power were high (r = 0.95-0.98, P < 0.02), consistent (before and after training) and valid (gain in standard error of estimate of 6 N or 2% of strength). The evidence suggested that maximum power was the strength stimulus. The maximum-power stimulus theory may unify and simplify theories of response and adaptation of structure and function induced by muscle.

A modification of the auscultatory blood pressure method, the phonoarteriogram, was developed. The innovated method essentially is a modified amplifying stethoscope. The pressure in the cuff is recorded from a pressure transducer, and the systolic and diastolic criteria are recorded from a microphone. The phonoarteriogram gives the advantages of a permanent record, includes pulse rate and pulse sound data, is not affected by hearing acuity, permits determinations often denied using auscultation in high ambient noise and exercise conditions, and eliminates observer bias. Three hundred and forty resting determinations and 218 exercise determinations on 60 subjects indicated good agreement between the phonoarteriogram and auscultation. In 50 systolic and diastolic intra-arterial determinations before compression of the cuff, during rest and exercise from one subject, the phonoarteriogram was as valid as auscultation. In 56 intra-arterial determinations during deflation of the cuff, i.e., simultaneous with the indirect measurements, during rest and exercise from a second subject, the phonoarteriogram was less fallible than auscultation, particularly during exercise. Phonoarteriograms are valid, reliable, and objective blood pressure record blood pressure determination; auscultatory blood pressure; intra-arterial blood pressure; physical fitness testing; ausculation; effort or physical effort; exercise; exertion; fatigue; methods, physiological; instrumentation; pulse; work Submitted on January 16, 1964

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