Effect of Resistance Training on VCAM-1 and Cortisol in HIV+ Men with Chemical Dependence

Effect of resistance training on VCAM-1 and Cortisol in HIV+ men with chemical dependence Curtis, John H., Vingren, Jakob L., Hill, David W., The Applied Physiology Laboratory, The University of North Texas, Denton, TX Resistance training can reduce the effects of inflammatory diseases and contribute to skeletal muscle repair and regeneration. Cortisol functions to reduce inflammation in the body however, it can impair the immune system. Elevated levels of Vascular Cell Adhesion Molecule 1 (VCAM-1) are associated with an increased risk of cardiovascular disease. Chemical dependency is also associated with immune impairment. Purpose: The purpose of this study was to look at the impact of resistance training on the level of cortisol and VCAM-1 as an inflammatory response to resistance training. Methods: Sixteen HIV+ men (Age: 41.5 ± 10.9, Height: 180.4 ± 9.1 cm, Weight: 89.2 ± 20.7 kg) enrolled in an in-patient chemical dependence rehabilitation program were recruited and assigned to one of two groups using randomization: supervised resistance training 3 times per week (Exercise) or no exercise training (Control) for six weeks. Before and after the 6-week period, a resting and fasted blood sample was obtained and analyzed for cortisol and VCAM-1 concentrations. Results: Resting levels of VCAM-1 were statistically unchanged in both the Control group (6.05 ± 4.5 vs. 6.13 ± 4.5) and in the Exercise group (7.05 ± 3.4 vs. 7.6 ± 3.6). Levels of Cortisol were also statistically unchanged in both the Control group (26.33 ± 9.3 vs. 26.08 ± 7.9) and the Exercise group (21.84 ± 3.5 vs. 22.37 ±4.8). Conclusion: A six week resistance training program might not be long enough to illicit the benefits of lower Cortisol levels and an increase in VCAM-1 levels in this given population

Use of Counter-balanced Smith Machine Affects Performance Measurements for Rebound Bench Press Throws

Rebound bench presses throws (RBT), often performed on a Smith machine, are used for assessment and training of upper body power. During a RBT, the stretch-shortening cycle potentiates performance in the concentric movement. Smith machines frequently utilize a counter-balance weight to reduce the net load on the barbell; however, the use of counter-balance weight affects measures of performance for RBT. PURPOSE: To evaluate how the use of a counter-balanced Smith machine affects performance measures for RBT. METHODS: Performance measures for the no counter-balanced (NCB) and counter-balanced (CB) RBT were assessed for 24 men (age: 23 ± 3 years, height: 179 ± 6 cm, mass: 91 ± 17 kg, bench press 1-repetition maximum [1RM]: 107 ± 18 kg). Each participant performed 2 sets of 2 repetitions of RBT for each condition at 30 % of their 1RM. Peak power, peak force, peak concentric and eccentric velocities, and duration of eccentric and concentric phases were measured using a linear accelerometer attached to the barbell; peak ground reaction force (GRF) was measured using a force plate. For each condition, data from the repetition with the highest peak power was used in further analyses. Peak EMG was measured for the right pectoral, deltoid and triceps muscles and normalized using peak EMG in the 1RM. RESULTS: Peak barbell measurements for power (NCB: 1220 ± 269 W, CB: 1069 ± 255 W), force (NCB: 906 ± 252 N, CB: 713 ± 143 N), and concentric (NCB: 2.54 ± 0.27 m•s-1, CB: 2.24 ± 0.32 m•s-1) and eccentric (NCB: -1.19 ± 0.46 m•s-1, CB: -0.95 ± 0.29 m•s-1) velocities were significantly (p\u3c0.05) higher for NCB compared to CB. The durations for the eccentric (NCB: 0.53 ± 0.16 s, CB: 0.64 ± 0.12 s) and concentric phases (NCB: 0.58 ± 0.58 s, CB: 0.77 ± 0.82 s), and peak pectoral EMG (NCB: 91 ± 21 % of 1RM, CB: 101 ± 24 % of 1RM) were lower for NCB compared to CB. Peak EMG for deltoid and triceps and peak GRF were unaffected by the use of counter-balance weights. CONCLUSION: The use of CB equipment resulted in reduced performance measurements (peak power, peak force, and peak eccentric and concentric velocities) for the RBT compared to NCB equipment. The lower peak eccentric stretch velocity likely resulted in a less effective stretch-shortening cycle for CB compared to NCB and thus helps explain the lower performance measurements found for CB

The Increase in Oxygen Demand During Severe Intensity Exercise Must be Included in Calculation of Oxygen Deficit

International Journal of Exercise Science 13(4): 645-655, 2020. A contentious element in the traditional method of calculating accumulated oxygen deficit (AOD) is the assumption that the oxygen demand remains constant throughout a bout of exercise. The purpose of this study was to investigate the appropriateness of this assumption. Twelve women and eight men volunteered for the study and completed cycle ergometer tests that resulted in exhaustion after ~4 min and ~8 min. In each test, AOD was calculated by subtracting accumulated oxygen uptake (in mL∙kg–1) from estimated total oxygen cost (in mL∙kg–1), which was estimating two ways: (i) assuming that oxygen demand (in mL∙kg–1∙min–1) increases over the course of the exercise bout and (ii) assuming it remains constant. Values for AOD in the 4-min and 8-min tests were expected to be the same (maximal). Mean values for AOD in the 4-min and 8-min tests were similar (79.1 ± 7.6 mL∙kg–1 and 79.6 ± 8.3 mL∙kg–1) when calculated assuming an increase in oxygen demand, but different (71.0 ± 7.9 mL∙kg–1 and 42.5 ± 7.6 mL∙kg–1) when the demand was kept constant. These results support the hypothesis that oxygen demand increases during exhaustive severe intensity cycling exercise. This increase must be included in calculation of AOD

Determining MAOD Using a Single Exhaustive Severe Intensity Test

International Journal of Exercise Science 13(4): 702-713, 2020. Maximal accumulated oxygen deficit (MAOD) provides a measure of anaerobic capacity. However, its measurement is a time-consuming process. The purpose of this study was to evaluate a measure of anaerobic capacity that avoids contentious assumptions and demands of the MAOD method. Twelve women and eight men volunteered for the study and completed cycle ergometer tests that resulted in exhaustion after ~4 min and ~8 min. In each test, anaerobic capacity was determined as (i) the MAOD and (ii) the sum of the phosphocreatine and glycolytic contributions (PCr+glycolysis). MAOD was determined by subtraction of the accumulated oxygen uptake from the total oxygen cost. Phosphocreatine and glycolytic contributions were calculated from post-exercise VO2 and blood lactate responses. MAOD in the 4-min and 8-min tests (79.1 ± 7.6 mL∙kg–1 and 79.6 ± 7.4 mL∙kg–1) and PCr+glycolysis in these tests (80.0 ± 7.3 mL∙kg–1 and 79.0 ± 6.9 mL∙kg–1) were correlated (r ≥ 0.91) and not significantly different. These results support the use of post-exercise measures to quantify the phosphocreatine and glycolytic contributions and to provide an alternative to MAOD for measurement of anaerobic capacity

Quadriceps foam rolling and rolling massage increases hip flexion and extension passive range-of-motion

Increases in joint range-of-motion may be beneficial for improving performance and reducing injury risk. This study investigated the effects of different self-massage volumes and modalities on passive hip range-of-motion. Twenty-five recreationally resistance-trained men performed four experimental protocols using a counterbalanced, randomized, and within-subjects design; foam rolling (FR) or roller massage (RM) for 60 or 120-s. Passive hip flexion and extension range-of-motion were measured in a counterbalanced and randomized order via manual goniometry before self-massage (baseline) and immediately, 10-, 20-, and 30-min following each self-massage intervention. Following FR or RM of quadriceps, there was an increase in hip flexion range-of-motion at Post-0 (FR: Δ = 19.28°; RM: Δ = 14.96°), Post-10 (FR: Δ = 13.03°; RM: Δ = 10.40°), and Post-20 (FR: Δ = 6.00°; RM: Δ = 4.64°) for all protocols, but these did not exceed the minimum detectable change at Post-10 for RM60 and RM120, and Post-20 for FR60, FR120, RM60, and RM120. Similarly, hip extension range-of-motion increased at Post-0 (FR: Δ = 8.56°; RM: Δ = 6.56°), Post-10 (FR: Δ = 4.64°; RM: Δ = 3.92°), and Post-20 (FR: Δ = 2.80°; RM: Δ = 1.92°), but did not exceed the minimum detectable change at Post-10 for FR60, RM60, and RM120, and Post-20 for FR60, FR120, RM60, and RM120. In conclusion, both FR and RM increased hip range-of-motion but larger volumes (120- vs. 60-second) and FR produced the greatest increases. These findings have implications for self-massage prescription and implementation, in both rehabilitation and athletic populations

Increasing Strength and Muscle Mass in HIV+ Men Recovering from Substance Abuse

The combination of substance (drug and/or alcohol) abuse and infection with human immunodeficiency virus (HIV) can result in the development of several co-morbidities, including muscle wasting. Resistance training could, therefore, be an important tool in the treatment of substance addiction/abuse and HIV. PURPOSE: The purpose of this study was to examine the effect of resistance training on measures of muscle mass and strength in the context of co-occurring substance abuse and HIV. METHODS: Seventeen untrained men (Mean ± SD: 42 ± 11 years, 89.7 ± 16.0 kg, 179.7 ± 9.1 cm, 18.9 ± 5.5 %fat) who are infected with HIV and enrolled in an in-patient substance addiction/abuse treatment program completed six weeks of either resistance training (RT) (three sessions per week) or no-exercise prescription (Control). Before (Pre) and after (Post) the 6-week period, anthropometric (e.g., body mass, skinfolds, and circumferences), strength (bench press and isometric squat), and power (vertical jumps) measurements were obtained. RESULTS: Predicted bench press 1-repetition maximum (1-RM) increased significantly (p\u3c0.05) for RT (Pre: 73.4 ± 23.4 kg; Post: 85.0 ± 30.4 kg) but not for Control (Pre: 54.9 ± 24.6 kg; Post: 57.3 ± 27.0 kg). Peak isometric squat force increased significantly for RT (Pre: 2627 ± 1071 N; Post: 2892 ± 1171 N) but not for Control (Pre: 2411 ± 675 N; Post: 2394 ± 592 N). Peak vertical jump power also increased significantly for RT (Pre: 35.9 ± 3.5 W·kg-1; Post: 36.2 ± 5.0 W·kg-1) but not for Control (Pre: 33.9 ± 3.9 W·kg-1; Post: 35.7 ± 4 W·kg-1). Muscle mass increased significantly for RT (Pre: 46.4 ± 8.2 kg; Post: to 50.5 ± 8.1 kg) but not for Control (Pre: 46.9 ± 13.0 kg; Post: 47.8 ± 12.4 kg). Upper arm and forearm circumference increased only for RT. No adverse effects of the resistance training program were observed. CONCLUSION: Resistance training for six weeks increases muscle strength and power, and induces muscle hypertrophy, in men who are infected with HIV and recovering from substance abuse. These findings support the efficacy for including resistance training in the standard of care for men with HIV undergoing in-patient treatment for substance addiction/abuse

Sex Differences in Change in Skin Temperature When Exercising in a Hot, Humid Environment

The risk for heat-related illness is increased when exercising in a hot, humid environment. In an effort to protect the athlete, body temperature is measured continuously while exercising in extreme environments. Currently, researchers and laboratory personnel employ the use of mean skin temperature to monitor athlete safety; however, this measurement fails to consider localized changes in temperature that may arise as a function of sex and exercise time. Therefore, the purpose of this study was to examine potential sex differences in the change in skin temperature at 17 different upper body locations while exercising in a hot, humid environment. Young men and women were recruited and completed a 60-min walk/jog interval protocol in a hot (34.1 ± 1 °C), humid (64 ± 8%) environment while skin temperature was continuously measured. To account for differences that may have arisen due to differing workloads between men and women, energy expenditure and metabolic heat production were calculated after the completion of exercise. Data was analyzed either a repeated-measures ANOVA (change in skin temperature) or t-test­ (energy expenditure and metabolic heat production). Location of interaction effects was determined using a Fisher’s Least Significant Difference test. Significance was set a p\u3c0.05 for all statistical testing. There was no difference between men and women in total energy expenditure; however, men were found to have a higher metabolic heat production. Women had a higher change in skin temperature at three locations on the back (left upper, right upper, and right mid-back). Conversely, there were no differences at any time point between men and women in the change in core temperature from baseline measurements. This study highlights the need to further investigate sex differences in cooling mechanisms while exercising in a hot, humid environment

The Effect of Pedaling Cadence on the Kinetics of Oxygen Uptake During Severe Intensity Exercise

During exhaustive severe intensity exercise, the oxygen uptake (VO2) increases exponentially, with a time constant of ~30 s. After ~1 to 2 min, a slow component emerges and drives the VO2 to its maximum. Pedaling cadence contributes to the metabolic demand at a given work rate and affects several responses to cycling exercise. PURPOSE: To determine the effect of pedaling cadence on parameters of the two-component VO2 response profile during severe intensity exercise. METHODS: Eight women (mean ± SD: age 22 ± 1 yr, height 161 ± 6 cm, and weight 58.8 ± 2.3 kg) and 10 men (age 23 ± 1 yr, height 180 ± 6 cm, and weight 82.9 ± 4.4 kg) performed exhaustive constant-power cycle ergometer tests using pedaling cadences of 60 rpm, 80 rpm, and 100 rpm. RESULTS: Times to exhaustion were smaller at higher cadences (220 ± 85 \u3c 299 ± 118 \u3c 368 ± 168 s), whereas VO2max values were the same at all cadences (2786 ± 729 = 2768 ± 749 = 2774 ± 732 ml/min). The mean response time of the primary response was faster at higher pedaling cadences (27 ± 5 \u3c 32 ± 5 \u3c 37 ± 5 s); the amplitude of the primary response was greater at the highest cadence (2045 ± 577 \u3e 1890 ± 493 = 1899 ± 515 ml/min); and the time delay before the slow component was smaller at higher cadences (85 ± 11 \u3c 105 ± 17 \u3c 118 ± 19 s). CONCLUSION: These results demonstrate that pedaling cadence affects the VO2 response profile. The higher cadences speed the primary or fundamental response and hasten the emergence of the slow component. This may have implications for the sport of cycling and should be considered when evaluating cardio-respiratory and metabolic responses to cycle ergometer exercise

The Effect of Work Rate on Oxygen Uptake Kinetics During Exhaustive Severe Intensity Cycling Exercise

The effect of work rate on oxygen uptake kinetics during exhaustive severe intensity cycling exercise Jennifer L. Sylvester, Samantha D. Burdette, Steven W. Cross, Nosa O. Idemudia, John, H. Curtis, Jakob L. Vingren, David W. Hill. Applied Physiology Laboratory, University of North Texas, Denton, TX During exhaustive severe intensity exercise, the oxygen uptake (VO2) increases exponentially, with a time constant of ~30 s. After ~1 to 2 min, a slow component emerges and drives the VO2 to its maximum. There are clear differences in the VO2 response profile across exercise intensity domains. These disparities might not be attributable to metabolic demand but, rather, to characteristics of the various intensity domains, such as the consequences of lactic acid production. PURPOSE: To investigate the role of exercise intensity on the VO2 response profile at intensities wholly within the severe domain. METHODS: Four women (mean ± SD: age 22 ± 2 years, height 167 ± 7 cm, mass 66 ± 5 kg) and eight men (age 23 ± 2 yr, height 179 ± 9 cm, mass 78 ± 10 kg) performed exhaustive constant-power cycle ergometer tests at two different severe intensity work rates (263 ± 78 W and 214 ± 64 W). Smoothed breath-by-breath VO2 data were fitted to a two-component (primary response and slow component) model using iterative regression. RESULTS: Times to exhaustion were 217 ± 27 s and 590 ± 82 s, respectively. The VO2max values were the same at the two different work rates (2973 ± 691 ml·min-1 and 3011 ± 728 ml·min-1). The amplitude of the primary response was greater (p \u3c 0.05) at the higher work rate (2095 ± 716 ml·min-1) than at the lower work rate (1857 ± 618 ml·min-1) and the amplitude of the slow component was smaller (367 ± 177 ml·min-1 vs 645 ± 347 ml·min-1). In addition, the time delay before the emergence of the slow component was shorter at the higher work rate (92 ± 22 s vs 116 ± 42 s). CONCLUSION: The results show that exercise intensity per se affects the VO2 response profile within the severe intensity domain and suggest that metabolic demand drives the primary response of VO2 kinetics within this domain. Category to be judged: Master\u27

Consumption of a high-fat meal increased monocyte adhesion molecule expression and oxLDL phagocytosis: implications for cardiovascular disease risk?

Macrophage-derived foam cells are the predominant component of arterial plaques in the early stages of atherosclerosis. The deposition of arterial plaques is effected by several factors that are influenced by a person’s daily nutritional habits. One factor that poses a major risk for plaque development is high levels of plasma LDL resulting from the consumption of a high-fat meal. In order to understand how an individuals’ diet effects arterial plaque deposition via the process of foam cell formation, we measured the acute response in circulating monocyte activity after consuming a high-fat meal. Samples were acquired on a FlowSight (EMD Millipore) equipped with 405, 488, 642, and 785 nm lasers. Samples were analyzed in IDEAS software to identify pro-inflammatory (CD14+/16+) and classic (CD14+/16-) monocytes. We measured monocyte concentration, adhesion molecule expression, scavenger R expression, and oxLDL phagocytosis for 5 h postprandial. We found that consuming a high-fat meal caused an increase in pro-inflammatory monocyte concentration, adhesion molecule expression, monocyte phagocytosis of oxLDL, and CD36 expression in pro-inflammatory monocytes. These results suggest that consuming a high-fat meal increases the potential of monocytes to become foam cells for at least 5 h postprandial