Robert J. Spina

Effect of Intensity of Aerobic Training on VO2max

PURPOSE To determine whether various intensities of aerobic training differentially affect aerobic capacity as well as resting HR and resting blood pressure (BP). METHODS Sixty-one health young adult subjects were matched for sex and VO2max and were randomly assigned to a moderate- (50% VO2 reserve (VO2R), vigorous (75% VO2R), near-maximal-intensity (95% VO2R), or a nonexercising control group. Intensity during exercise was controlled by having the subjects maintain target HR based on HR reserve. Exercise volume (and thus energy expenditure) was controlled across the three training groups by varying duration and frequency. Fifty-five subjects completed a 6-wk training protocol on a stationary bicycle ergometer and pre- and posttesting. During the final 4 wk, the moderate-intensity group exercised for 60 min, 4 d.wk the vigorous-intensity group exercised for 40 min, 4 d.wk and the near-maximal-intensity group exercised 3 d.wk performing 5 min at 75% VO2R followed by five intervals of 5 min at 95% VO2R and 5 min at 50% VO2R. RESULTS VO2max significantly increased in all exercising groups by 7.2, 4.8, and 3.4 mL.min.kg in the near-maximal-, the vigorous-, and the moderate-intensity groups, respectively. Percent increases in the near-maximal- (20.6%), the vigorous- (14.3%), and the moderate-intensity (10.0%) groups were all significantly different from each other (P < 0.05). There were no significant changes in resting HR and BP in any group. CONCLUSION When volume of exercise is controlled, higher intensities of exercise are more effective for improving VO2max than lower intensities of exercise in healthy, young adults.

Cross-modal exercise prescription at absolute and relative oxygen uptake using perceived exertion.

Cross-modal exercise prescription at absolute and relative oxygen uptake using perceived exertion. Med. Sci. Sports Exerc., Vol. 22, No. 5, pp. 653-659, 1990. The validity of cross-modal prescription of exercise intensity based on rated perceived exertion (RPE) was determined for eight men (26 +/- SE 1.9 yr) at absolute and relative VO2. Exercise modes were treadmill (TM), cycle ergometer (C), and bench stepping while pumping 0.91 kg handweights (HB). Relative (Rel) constant load sessions were performed for each mode at 70% of mode-specific VO2 peak. Absolute (Absol) constant load sessions were performed for C and HB at the VO2 equivalent to 70% of TM VO2 peak. The five 12 min sessions were presented on separate days in random order. RPE-Overall during TM-Rel (11.1) was a) lower (P less than 0.05) than C-Absol (12.6) and HB-Absol (12.5) and b) the same as C-Rel (11.3) and HB-Rel (10.7). RPE-Legs during TM-Rel was a) lower (P less than 0.05) than C-Absol and HB-Absol and b) the same as C-Rel and HB-Rel. RPE-Chest a) did not differ between TM-Rel and C-Absol or HB-Absol and b) was lower (P less than 0.05) for C-Rel and HB-Rel than TM-Rel. RPE-Arms was higher (P less than 0.05) for C-Absol, HB-Absol, and HB-Rel than TM-Rel but did not differ between TM-Rel and C-Rel. Oxygen uptake, heart rate, and ventilation during TM-Rel were a) the same as C-Absol and HB-Absol and b) higher (P less than 0.05) than C-Rel and HB-Rel. Perceptually based cross-modal prescription of exercise intensity using a psychophysical estimation method is valid provided that the physiological reference is the relative, not the absolute, VO2.

Specificity of arm training on aerobic power during swimming and running.

The specificity of aerobic training for upper-body exercise requiring differing amounts of muscle mass was evaluated in 25 college-aged male recreational swimmers who were randomly assigned to either a non-training control group (N = 9), a 10-wk swim(S)-training group (N = 9), or a group that trained with a standard swim-bench pulley system (SB; N = 7). For all subjects prior to training, tethered-swimming peak VO2 averaged 19% below treadmill values (P less than 0.01), while SB-ergometry peak VO2 was 50% and 39% below running and swimming values, respectively (P less than 0.01). Significant (P less than 0.01) increases of peak VO2 in tethered swimming (11%) and SB (21%) were observed for the SB-trained group, while the S-trained group improved (P less than 0.01) 18% and 19% on the tethered swimming and SB tests, respectively. No changes were observed during treadmill running, and the control subjects remained unchanged on all measures. Comparisons between training groups indicated that although both groups improved to a similar extent when measured on the swim bench, the 0.53 l X min-1 improvement in tethered-swimming peak VO2 for the S-trained group was greater (P less than 0.05) than the 0.32 l X min-1 increase noted for the SB-trained group. The comparisons between SB and S exercise vs treadmill exercise support the specificity of aerobic improvement with training and suggest that local adaptations contribute significantly to improvements in peak VO2. Furthermore, the present data indicate that SB exercise activates a considerable portion of the musculature involved in swimming, and that aerobic improvements with SB training are directly transferred to swimming.

Autonomic Response to Tactical Pistol Performance Measured by Heart Rate Variability

Abstract Thompson, AG, Swain, DP, Branch, JD, Spina, RJ, and Grieco, CR. Autonomic response to tactical pistol performance measured by heart rate variability. J Strength Cond Res 29(4): 926–933, 2015—This study evaluated changes in autonomic tone during a tactical pistol competition. At rest and during a match, heart rate variability (HRV) was examined in 28 healthy subjects. Heart rate variability time-domain variables (including interbeat interval [IBI]) and frequency-domain variables (low frequency [LF], high frequency [HF], total power [TP]) measured during shooting were subtracted from those measured during rest to produce &Dgr;s. The shooting task involved several, rapid tactical maneuvers. Raw time to completion and inaccurate shots (points down [PDs]) were recorded and combined to form a match score where lower values indicated superior shooting performance. Mean (±SD) raw time was 135.9 ± 34.1 seconds, PDs were 78 ± 34, and match score was 175.3 ± 39.8. Shooting decreased IBI (i.e., increased heart rate) and LF. &Dgr;LF, &Dgr;HF, and &Dgr;TP were independent of &Dgr;IBI. Raw time was significantly (p ⩽ 0.05) correlated to shooting IBI (r = 0.404) and &Dgr;IBI (r = −0.426). Points down were significantly correlated to &Dgr;TP (r = 0.416) and &Dgr;LF (r = 0.376). Match score was significantly correlated to &Dgr;IBI (r = −0.458), &Dgr;HF (r = 0.467), &Dgr;LF (r = 0.377), and &Dgr;TP (r = 0.451). In conclusion, individuals with a greater decrease in IBI (and thus heart rate) performed better by accomplishing the match faster. Individuals with less change in stress-related HRV measures (LF, HF, and TP) performed better through improved accuracy. Thus, HRV-derived sympathetic response is significantly related to shooting performance and should be used to assess marksmanship effectiveness under duress.

Amino acid arterial concentration and muscle exchange during submaximal arm and leg exercise: The effect of dihydroxyacetone and pyruvate

The mixture of dihydroxyacetone and pyruvate (DHAP) is an ergogenic aid that enhances muscle glucose extraction during prolonged aerobic exercise. In order to evaluate the effect of DHAP on muscle amino acid extraction during exercise, we measured arterial concentration and muscle exchange of amino acids in 18 untrained healthy male subjects (aged 20-30 years) performing dynamic arm (60% VO2 max, n = 9) or leg (70% VO2 max, n = 9) exercise to exhaustion with and without dietary supplementation of DHAP. The subjects consumed diets (146 kJ kg body weight-1 day-1) containing either 100 g polyglucose, Polycose (placebo, P) or DHAP (3:1, treatment) substituted for a portion of carbohydrate. The two diets were administered in a double-blind, random, crossover order for a 7-day period. At least 7 days separated the dietary protocols. Blood samples were drawn through radial artery and axillary or femoral vein catheters at rest, during exercise and at exhaustion. Arterial alanine concentration increased by 30% during arm exercise and by 50-60% during leg exercise. No other arterial amino acid concentration changed during exercise. At exhaustion, arterial alanine concentration decreased to pre-exercise levels with arm exercise but remained elevated after leg exercise. Despite changes in arterial concentrations of alanine with exercise, muscle exchange of alanine was not altered with exercise. Exercise did not alter muscle exchange of any amino acid. Arterial amino acid concentrations and muscle exchange of amino acids with exercise were similar with or without DHAP feeding.(ABSTRACT TRUNCATED AT 250 WORDS)

Aerobic metabolic requirements of simulated cross-country skiing

This study evaluated the aerobic metabolic requirements of simulated cross-country skiing. Five male subjects exercised on a cross-country skiing machine at 12 different arm and leg resistances and movement frequencies. Oxygen consumption (VO2) ranged from 21.6 to 44.4 ml kg(-1) min(-1). The VO2 increased significantly (p less than 0.05) as the frequency of limb movement was increased. These data suggest that simulated cross-country skiing places a significant demand on the aerobic metabolic system and as such is a viable alternative to conventional cardiovascular exercise modalities.