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The purpose of the present study was to derive a regression equation relating variables obtained from a series of noninvasive functional tests in a normal subject population to the fiber type distribution of vastus lateralis muscle (VL) determined using muscle biopsy. All functional tests were designed to distinguish between basic properties of Type II fibers (fast twitch fibers) and Type I fibers (slow twitch fibers) and included assessment of peak torque, power output at nine different angular velocities (60 degrees.s-1 to 300 degrees.s-1), as well as a fatigue test consisting of 60 consecutive contractions at 90 degrees.s-1 to establish fatigue resistance of the knee extensor muscles. Using a stepwise multiple regression procedure, relative torque after 53-55 contractions (T55) in the fatigue test and power output at an angular velocity of 280 degrees.s-1 normalized for fat free mass of the thigh (FFMT) were the best predictors for fiber type distribution, explaining 51.8% of the variance in the proportion of Type II fibers in VL. No other measured variable met entering criteria. Subgroup analyses revealed a higher peak torque/FFMT, higher power/FFMT values at angular velocities of 200 degrees.s-1 and higher, and lower relative torque beyond 30 contractions in the fatigue test for the fast twitch group, FTG (subjects with > 60% Type II fibers, N = 8) as compared with the STG (subjects with < 45% Type II fibers, N = 9). Results from the present study suggest that two simple functional tests on a Cybex dynamometer yield reasonable estimates of the fiber type distribution in VL.

Salbutamol and treadmill performance in non-atopic athletes. Med. Sci. Sports Exerc., Vol. 15, No. 6, pp. 520-522, 1983. Nineteen aerobic, non-atopic, athletes (10 females, 9 males) were studied in a double-blind fashion to determine the effect of a therapeutic dosage of salbutamol on pulmonary function, oxygen consumption (VO2max), heart rate (HR), and anaerobic threshold (AT). A placebo and salbutamol (in aerosol form) were administered in a dosage of two puffs four times per day. Forced vital capacity (FVC), FEV1.0, and mid-maximal expiratory flow were assessed prior to a maximal treadmill run, and at 5, 10, and 15 min of recovery. Resting and maximal HR, VO2max, AT, and VE were determined prior to and immediately after the 1-wk experimental period. Pre-test results showed no evidence of airway obstruction in any athlete. There was no significant change in any pulmonary function variable as a result of salbutamol administration. Maximal oxygen consumption showed a slight, nonsignificant (P greater than 0.05) decrease in both the salbutamol and placebo groups. There was also a similar nonsignificant decrease in pulmonary function in both groups. Resting and maximal HR and AT were unchanged. These results indicate that therapeutic administration of a selective beta-2 agonist does not affect pulmonary function or performance-related variables in non-atopic elite athletes.