Male-Female Differences in Push-up Test Performance at Various Cadences.

ABSTRACT: Rozenek, R, Byrne, JJ, Crussemeyer, J, and Garhammer, J. Male-Female Differences in Push-up Test Performance at Various Cadences. J Strength Cond Res 36(12): 3324-3329, 2022-Push-up (PU) testing is widely used to assess upper-extremity muscular endurance. However, little information exists regarding the influence of cadence on PU performance. Forty-four healthy men and women (age range = 21-36 years) completed 4 PU test sessions on separate days in a randomized order using standard PUs. Cadences of 30, 45, and 60 PU·min -1 were used for 3 tests, whereas a fourth test was performed at a self-selected (SS) cadence. The total number of PUs completed, vertical ground reaction forces (vGRFs) acting on each hand and the feet, and the sum of the vGRFs were determined for each test. Results showed men performed more PU than women at any cadence ( p ≤ 0.05) and had a faster mean SS cadence (49.9 ± 11.4 PU·min -1 vs 42.8 ± 8.4 PU·min -1 ) ( p ≤ 0.05). The maximum number of PU were performed when using either the SS cadence or 60 PU·min -1 , with little difference observed between them ( p ≤ 0.05). The sum of vGRFs was greatest at 60 PU·min -1 and when scaled to body mass (BM) represented 1.58 ± 0.14x and 1.33 ± 0.08x BM for men and women, respectively. As cadence increased, men shifted more weight to the hand contact points compared with women ( p ≤ 0.05). Distinct differences in SS cadence and distribution of forces were observed between the sexes suggesting different strategies while performing the PU test. These differences should be considered when selecting a protocol for PU testing.

Effects of a 6-Week Upper Extremity Low-Volume, High-Intensity Interval Training Program on Oxygen Uptake, Peak Power Output, and Total Exercise Time.

Pinto, N, Salassi III, JW, Donlin, A, Schroeder, J, and Rozenek, R. Effects of a 6-week upper extremity low-volume, high-intensity interval training program on oxygen uptake, peak power output, and total exercise time. J Strength Cond Res 33(5): 1295-1304, 2019-The purpose of this study was to compare the effects of upper extremity (UE) high-intensity interval training (HIIT) to UE continuous training (CT) when training at a similar intensity. Twenty participants (mean age = 23 ± 3 years) were randomly assigned to either a HIIT (n = 10) or CT (n = 10) group. Participants completed a graded exercise test (GXT) utilizing arm cranking before and after 6 weeks (2 sessions per week) of UE training. During sessions, HIIT performed 10 repetitions of 60 seconds of work at 92.3 ± 1.0% of the arm HRpeak (%aHRpeak) and 60 seconds of passive recovery (%aHRpeak = 73.0 ± 4.0%) yielding an average training intensity of 82.6 ± 1.5 %aHRpeak. CT exercised for 20 minutes at an average intensity of 81.9 ± 2.2 %aHRpeak. After training, HIIT showed greater improvement in V[Combining Dot Above]O2peak compared with CT (Δ = 4.1 ml·min·kg, 95% confidence interval [CI]: 1.3-6.9 m·min·kg, p = 0.007). Total exercise time during the posttest GXT was also improved as a result of HIIT (Δ = 1.4 minutes, 95% CI: 0.4-2.3 minutes, p = 0.008). Both groups improved peak power output, but no difference was observed between them (Δ = 3.3 W, 95% CI: -3.3 to 9.9 W, p = 0.305). For a similar time investment, HIIT seemed to improve measures of cardiopulmonary capacity and exercise time to a greater extent than CT and may be a time-efficient alternative for those who incorporate UE aerobic activity into a training program.

Acute Cardiopulmonary and Metabolic Responses to High-Intensity Interval Training Protocols Using 60 s of Work and 60 s Recovery.

Rozenek, R, Salassi III, JW, Pinto, NM, and Fleming, JD. Acute cardiopulmonary and metabolic responses to high-intensity interval training protocols using 60 s of work and 60 s recovery. J Strength Cond Res 30(11): 3014-3023, 2016-Low-volume, high-intensity interval training (HIIT) consisting of 60 s work and 60 s recovery (60 s/60 s) repeated for 10 times has previously been found to produce beneficial cardiopulmonary, cellular, and metabolic adaptations in healthy and at-risk populations. There is currently relatively little information pertaining to the acute changes that take place during individual training sessions. The purpose of this study was to examine the acute physiological responses to 60 s/60 s × 10 HIIT protocols using several combinations of work and recovery intensities. Eleven healthy adults (mean age ± SD = 26.0 ± 5.3 years) performed 4 HIIT trials on separate days at varying percentages of peak power output that consisted of the following work/recovery intensities: (a) 80% PPO/0% PPO (80/0); (b) 80% PPO/50% PPO (80/50); (c) 100% PPO/0% PPO (100/0); and (d) 100% PPO/50% PPO (100/50). Compared with the other protocols, 100/50 produced higher (p ≤ 0.05) peak, average, and nadir %V[Combining Dot Above]O2peak. Other than the nadir values resulting from the 80/0 trial, all trials produced average, peak, and nadir %V[Combining Dot Above]O2peak and %HRpeak values that were within exercise intensity ranges (≈45-90% V[Combining Dot Above]O2max; ≈65-90% HRmax) recommended by the American College of Sports Medicine for improvement of cardiopulmonary function. Similar average HR and peak HR, RPE, blood lactate, and %V[Combining Dot Above]O2peak values were produced by 80/50 and 100/0 protocols. However, the average %V[Combining Dot Above]O2peak was significantly higher (∼9.3% absolute) in 80/50. It appeared that use of the 80/0, 80/50, and 100/0 protocols would be appropriate for individuals who are at the low to moderate end of the cardiopulmonary fitness spectrum.

The Relationship Between Pedometer-Determined Ambulatory Activity and Balance Variables Within an Older Adult Population.

The purpose of this investigation was to determine the differences between gender, physical activity level, and balance in an older adult population. A secondary purpose was to examine the relationship between pedometer-determined ambulatory activity and balance. Forty-six older adults aged 73.7 ± 6.2 years participated in the study. Participants completed the Fullerton Advanced Balance (FAB) Scale and completed a 2-week daily step recording to determine average steps taken per day. Low-level activity participants (<5,000 steps/day) were significantly different from the high-level activity participants (>7,500 steps/day) in weight, age, and the number of medications reported. Males performed better than females on the two-footed jump test and reactive postural test FAB assessments. High-level activity participants performed significantly better than low-level activity participants on all FAB assessments except stand with feet together and eyes closed, reach forward to object, and walk with head turns.

Anthropometry and barbell trajectory in the snatch lift for elite women weightlifters.

The primary objective of this study was to examine relationships between anthropometry and horizontal barbell displacement during the pulling phase of the snatch lift (SN) in elite women weightlifters. Secondary objectives included description of anthropometric and displacement characteristics, and examinations of SN performance and competitive experience. Thirty-six women weightlifters competing at the 2009 Pan American Championships participated. Participants were measured for standing height, upper limb, trunk, thigh, and shank lengths, and completed a questionnaire about competition and training experience. Horizontal displacement from lift-off to first pull maximum (Dx1) and from first pull to second pull maximum (Dx2) was determined from the heaviest successful SN using 2-dimensional video analysis. Significant correlations (p ≤ 0.05) existed between thigh and lower-limb lengths and Dx2 in 53 kg participants; lower-limb length and Dx1 in 75 kg participants; and horizontal displacement and body segment ratios involving the upper and lower extremity in multiple weight classes. Correlations between anthropometry and Dx1 also reached significance with participants grouped by barbell trajectory type. Except for the trunk and thigh, body segment lengths were significantly different (p ≤ 0.05) between weight classes. Significantly different body proportions existed in 48 kg participants compared with all other classes. Multiple thigh and trunk variables were significantly correlated with performance. Horizontal displacement values were similar to previous reports in the literature. Few significant relationships existed between displacement and performance, and none were found for competitive experience. Understanding relationships between anthropometry and barbell trajectory may be useful for optimizing SN technique.

Bone mineral density and body composition of collegiate modern dancers.

This study investigates body composition (BC), bone mineral density (BMD), eating behaviors, and menstrual dysfunction in collegiate modern dancers. Thirty-one female collegiate modern dance majors (D), 18 to 25 years of age, and 30 age-matched controls (C) participated in the study. BC and BMD were measured using dual energy x-ray absorptiometry (DXA). Upper and lower body strength was assessed by chest and leg press one-repetition maximum tests. Participants completed three-day food records, and the diet was analyzed using nutritional software. Menstrual dysfunction (MD) and history of eating disorder (ED) data were collected via questionnaires. BC and BMD variables were analyzed using MANCOVA and frequency of ED and MD by Chi-Square analysis. BMD was greater in D than C at the spine (1.302 ± 0.135 g/cm(2) vs. 1.245 ± 0.098 g/cm(2)), and both the right hip (1.163 ± 0.111 g/cm(2) vs. 1.099 ± 0.106 g/cm(2)) and left hip (1.160 ± 0.114 g/cm(2) vs. 1.101 ± 0.104 g/cm(2); p ≤ 0.05). Total body fat percentage was lower in D than C (25.9 ± 4.2% vs. 32.0 ± 5.9%; p ≤ 0.05), and percent of fat distributed in the android region was also lower in D than C (28.0 ± 6.2% vs. 37.6 ± 8.6%; p ≤ 0.05). With regard to diet composition, only percent fat intake was lower in D than C (27.54 ± 6.8% vs. 31.5 ± 7.4%, p ≤ 0.05). A greater incidence of ED was reported by D than C (12.9% vs. 0%; p ≤ 0.05), as well as a greater incidence of secondary amenorrhea (41.9% vs 13.3%; p ≤ 0.05). No differences were found for incidence of primary amenorrhea, oligomenorrhea, or use of birth control. Strength values were higher in D than C for both chest press (30.1 ± 0.9 kg vs. 28.4 ± 1.0 kg; p ≤ 0.05) and leg press (170.7 ± 4.2 kg vs.163.1 ± 3.9 kg; p ≤ 0.05). It is concluded that the dancers in our study had a healthy body weight, yet reported a higher incidence of eating disorders and menstrual dysfunction, than non-dancers. These dancers' higher BMD may be attributable to the mechanical loading and increased strength associated with practicing modern dance. Further, modern dancers had lower centrally located body fat, which decreases the risk for cardiovascular and metabolic diseases.

Does hyperbaric oxygen exposure affect high-intensity, short-duration exercise performance?

Hyperbaric oxygen (HBO) exposure involves the breathing of 100% oxygen under conditions of elevated atmospheric pressure and is used to increase the oxygen content of the plasma fraction of arterial blood. The purpose of this study was to determine the effects of acute HBO exposure on selected physiological responses and performance in response to maximal lower extremity or upper extremity short-term, high-intensity exercise. The study was performed with 2 separate experiments incorporating double-blinded and randomized protocols. In experiment 1, 9 subjects ran on a treadmill at a speed of 268 m x min(-1) with a predetermined grade. In experiment 2, 9 different subjects performed a repetitive bench press exercise. Both exercise protocols were designed to induce fatigue within 1-2 minutes. Within each experiment, subjects received either a 1-hour HBO exposure inspiring 100% O2 at 202.6 kPa (2.0 atmospheres absolute pressure [ATA]) or a 1-hour sham exposure inspiring ambient air at 121.5 kPa (1.2 ATA) before exercise. No significant differences (p > or = 0.05) were observed in postexercise blood lactate concentrations, peak heart rate, ratings of perceived exertion, or performance as determined by treadmill running time or number of completed lifts. Unlike other methods that elevate oxygen content of the blood, acute HBO exposure appears to have no significant effect on subsequent high-intensity running or lifting performance.

Comparison of three methods for detection of the lactate threshold.

The lactate threshold (LT) represents the onset of a metabolic acidosis during graded exercise testing (GXT). It is a valuable measurement in clinical exercise testing and correlates well with endurance performance. Our purpose was to compare three LT detection methods, namely, Inspection (work rate at onset of a systematic increase in blood lactate concentration determined by inspection of blood lactate versus work rate plot), 0.5 mM (work rate which just precedes a rise in blood lactate concentration of >0.5 mM) and log-log (work rate at the intersection of two linear lines in plot of log lactate versus log work rate where the residual sum of squares for both lines added together is minimized). Fourteen subjects underwent cycle ergometer GXT with blood samples obtained at the end of each 3-min work rate increment and analysed for lactate concentration. The mean +/- 95% confidence limits of work rates at LT for the Inspection, 0.5 mM and log-log methods were 104.5 +/- 28.0, 103.2 +/- 28.1 and 105.1 +/- 27.3 W, respectively. Repeated-measures analysis of variance yielded a non-significant F ratio. The Bland-Altman bias +/- 95% limits of agreement for Inspection versus 0.5 mM, Inspection versus log-log and 0.5 mM versus log-log were 1.3 +/- 20.6, -0.6 +/- 12.5 and -1.9 +/- 20.5 W, respectively. The intraclass correlation coefficients for Inspection versus 0.5 mM, Inspection versus log-log and 0.5 mM versus log-log were 0.978, 0.992 and 0.977, respectively. The results of this study suggest that all three methods detect the LT at the same work rate.

Physiological responses to interval training sessions at velocities associated with VO2max.

Previous research has indicated that short-duration, high-intensity work intervals performed at velocities associated with maximal oxygen uptake (vVO2max) combined with active recovery intervals may be effective in eliciting improvements in endurance performance. This study was designed to characterize selected physiological responses to short-duration (< or = 60 seconds) interval work performed at velocities corresponding to 100% of vVO2max. Twelve men participated in 3 randomized trials consisting of treadmill running using work (W)/recovery (R) intervals of 15 seconds W/15 seconds R (15/15); 30 seconds W/15 seconds R (30/15); and 60 seconds W/15 seconds R (60/15). Work intervals were performed at 100% of vVO2max, whereas R intervals were performed at 50% of vVO2max. A fourth trial consisting of continuous work (C) at 100% of vVO2max was also performed. All subjects completed the 15/15 and 30/15 trials; however, only 5 of the 12 completed the 60/15 trial. The percentage of VO2max (mean +/- SD) during 15/15 (71.6 +/- 4.2%) was significantly lower (p < or = 0.05) than the percentages during 30/15 (84.6 +/- 4.0%), 60/15 (89.2 +/- 4.2%), or C (87.9 +/- 5.0%). Similar results were found for heart rate and perceived exertion. Blood lactate concentrations following exercise were significantly lower (p < or = 0.05) in 15/15 (7.3 +/- 2.4 mmol x L(-1)) than in the other trials. No significant differences (p > 0.05) existed among 30/15 (11.5 +/- 1.8 mmol x L(-1)), 60/15 (12.5 +/- 1.8 mmol x L(-1)) or C (12.1 +/- 1.8 mmol x L(-1)). High intensity, short-duration 2:1 W/R intervals appear to produce responses that may benefit both aerobic and anaerobic energy system development. A 4:1 W/R ratio may be an upper limit for individuals in the initial phases of interval training.

Effect of plasma volume loss during graded exercise testing on blood lactate concentration.

Previous studies have shown that plasma volume (PV) loss can be a confounding variable in the interpretation of changes in blood constituents. We examined the effect of PV loss on three features of the blood lactate versus work-rate relationship, namely, slight blood lactate increase during the early stages of graded exercise testing (GXT); work rate at the onset of a systematic increase in blood lactate, i.e., lactate threshold (LT); and work rate at a blood lactate concentration of 4 mM, i.e., onset of blood lactate accumulation (OBLA). Fourteen subjects underwent cycle ergometer GXT. Blood samples were obtained at rest and at the end of each 3-min work-rate increment and analyzed for hematocrit and lactate concentration. For exercise levels up to and including LT, PV loss was relatively stable at approximately 2.8%. Beyond LT, PV loss accelerated. From the first work rate to LT, blood lactate concentration uncorrected for PV loss increased 0.24 +/- 0.07 mM (P < 0.05). After correction for PV loss, the increase was 0.21 +/- 0.08 mM (P < 0.05). These mean increases were not significantly different from each other. For the four exercise levels above LT common to most subjects, PV-corrected lactate values were significantly lower than uncorrected values. Correction of lactate values for PV loss did not alter LT for any subject, but it did result in a significant increase in OBLA. Thus, PV loss has the potential to be a confounding variable for the interpretation of blood lactate parameters that are determined at exercise levels above LT.

Effects of delayed onset muscle soreness on selected physiological responses to submaximal running.

This study examined the effects of delayed-onset muscle soreness (DOMS) on selected physiological responses to submaximal exercise. Seven male and four female subjects (Ss) aged 21-37 years completed two submaximal running sessions at an individualized pace corresponding to a blood lactate concentration (bLa) of approximately 2.5 mmol x L(-1). Following the first session (T1), Ss performed a series of lower extremity resistance exercises designed to induce DOMS. Subjects were then retested (T2) 24-30 hours later, during which time all Ss experienced DOMS. Oxygen uptake, heart rate (HR), respiratory exchange ratio, rating of perceived exertion (RPE), and bLa were measured every 6 minutes. Significant trial effects (p < 0.05) were observed for HR and RPE. HR was significantly higher during T1 at minutes 6 and 12 (p < 0.05), and RPE values were significantly higher at T2 during all recording periods (p < 0.05). Results from this study suggest that DOMS does not affect submaximal oxygen uptake. However, DOMS does appear to affect one's perception of effort.