The differences between sand and indoor volleyball courts can affect an athlete’s performance, most notably jumping and agility performance. Maximal jumps have been reported to be lower when performed on sand compared to rigid surfaces similar to a wood-flooring court. PURPOSE: To examine the performance of elite female sand and indoor collegiate volleyball players in agility and approach jump testing in sand and on an indoor surface; including heart rates and ratings of perceived exertion. METHODS: Participants (n=21, age 19.8±1.1yrs, height 1.78±0.08m, body mass 73.62±9.63kg) were members of NCAA Division I women’s indoor and sand volleyball teams who finished their seasons ranked in the top 8 nationally. Two thirty minute sessions (one sand, one indoor) were completed, consisting of the approach jump test and the 4 Cone Star Drill with a five minute rest between tests. At least three trials were completed for each test and the outcome measures were the participant’s approach jump (cm) and agility time (sec), as well as their ratings of perceived exertion (RPE) and heart rate recovery (HRR) following agility testing. RESULTS: There was a significant difference between surfaces for both approach jump (57.57±6.28cm indoor vs. 51.03±5.47cm sand, mean difference 6.5±4.3cm, p<0.001) and agility trials (6.66±0.52sec indoor vs. 6.96±0.60sec sand, mean difference 0.30±0.46sec, p=0.021), but not in HRR (36.4±10.2bpm indoor vs. 36.3±9.9bpm sand, p>0.05), peak HR (139.5±12.1bpm indoor vs. 142.3±11.9bpm sand, p>0.05), and RPE (9.6±2.1 indoor vs. 9.4±2.2 sand, p>0.05). There were no significant differences in approach jump or agility time for athletes who competed in sand, indoor, or both (p>0.05 for all), although the difference in RPE trended towards significance (p=0.082). Although not significant, sand athletes and hybrid (compete in sand and indoor) athletes consistently performed better than indoor athletes on both surfaces (mean difference 0.593±0.238 sec and 0.553±0.79 sec, respectively). CONCLUSIONS: Significant differences exist between sand and indoor surfaces when performing approach jump and agility drills, but not between sand and indoor volleyball athletes.
Background: A prospective study was conducted in human immunodeficiency virus (HIV)-infected patients as they undergo alterations in their antiretroviral therapy (ART) to determine the effect of ART on autonomic function.Methods: HIV-infected subjects who were either 1) naïve to ART and initiating ART, or 2) receiving ART and in HIV virologic failure for at least 4 months and were about to switch ART were enrolled in this study.Autonomic function assessment (cardiovagal, adrenergic, and sudomotor tests) was performed prior to and 4 months after initiating the new ART.Changes in clinical autonomic symptoms and virologic assessment were assessed.Results: Twelve subjects completed the study: 92% male; median age (Q1, Q3) was 41.0 (28.0, 48.2) years; and 50% White/Non-Hispanic.Seventy-five percent were ART naïve while 25% were failing their ART regimen.The median CD4 count was 336.5 (245.3,372.3) cells/mm 3 .All subjects achieved an undetectable HIV viral load by the 4-month follow-up visit.The majority of naïve subjects were started on an ART regimen of tenofovir / emtricitabine / efavirenz.There were no significant differences in autonomic function assessment, as measured by cardiovagal, adrenergic, and sudomotor tests, with regards to ART initiation.Conclusion: This is the first study to examine the effects of initiating ART on autonomic function in early HIV infection.This study found no appreciable differences of ART on the autonomic nervous system when ART is initiated early in the course of HIV disease.ART may not contribute to short-term changes in autonomic function.
In HIV-infected individuals, impaired mitochondrial function may contribute to cardiometabolic disease as well as to fatigue and frailty. Aerobic exercise improves total body energy reserves; however, its impact at the cellular level is unknown. We assessed alterations in cellular bioenergetics in peripheral blood mononuclear cells (PBMC) before and after a 12-week aerobic exercise study in sedentary HIV-infected subjects on stable antiretroviral therapy who successfully completed a 12-week aerobic exercise program. In this prospective study, participants underwent supervised 20-40 min of light aerobic exercise (walking or jogging) performed three times per week for 12 weeks, gradually increasing to maintain an intensity of 50%-80% of heart rate reserve. Maximal aerobic capacity (VO2MAX) was assessed by a graded exercise test on a cycle ergometer before and after completion of the study. PBMC from compliant subjects (attended at least 70% of exercise sessions) were assessed for mitochondrial respiration using the Seahorse XF24 Bio-Analyzer. Seven of 24 enrolled subjects were compliant with the exercise regimen. In these individuals, a significant increase (p = .04) in VO2MAX over 12 weeks was found with a median increase of 14%. During the same interval, a 2.45-fold increase in PBMC mitochondrial respiratory capacity (p = .04), a 5.65-fold increase in spare respiratory capacity (p = .01), and a 3.15-fold (p = .04) increase in nonmitochondrial respiration was observed. Aerobic exercise improves respiration at the cellular level. The diagnostic and prognostic value of such improved cellular respiration in the setting of chronic HIV warrants further investigation.
This retrospective study evaluated the frequencies of symptoms associated with autonomic dysfunction in human immunodeficiency virus (HIV)-infected patients on stable combined antiretroviral therapy. Patients infected with HIV reported higher frequencies of dysautonomia symptoms compared with HIV-negative patients, particularly in the autonomic domains related to urinary, sleep, gastroparesis, secretomotor, pupillomotor, and male sexual dysfunction.
Due to the high number of adolescent athletes and subsequent lower extremity injuries, improvements of injury prevention strategies with emphasis on clinic-based and practical assessments are warranted.The purpose of this study was to prospectively investigate if a battery of functional performance tests (FPT) could be used as a preseason-screening tool to identify adolescent athletes at risk for sports-related acute lower extremity injury via comparison of injured and uninjured subjects.One hundred adolescent volleyball, basketball and soccer athletes (female, n=62; male, n=38; mean age = 14.4 ± 1.6) participated. The FPT assessment included: triple hop for distance, star excursion balance test, double leg lowering maneuver, drop jump video test, and multi-stage fitness test. Composite scores were calculated using a derived equation. Subjects were monitored throughout their designated sport season(s), which consisted of a six-month surveillance period. The schools certified athletic trainer (ATC) recorded all injuries. Subjects were categorized into groups according to sex and injury incidence (acute lower extremity injury vs. uninjured) for analysis.Mean FPT composite scores were significantly lower for the injured compared to the uninjured groups in both sexes (males: 19.06 ± 3.59 vs. 21.90 ± 2.44; females: 19.48 ± 3.35 vs. 22.10 ± 3.06 injured and uninjured, respectively)(p < .05). The receiver-operator characteristic analysis determined the cut-off score at ≤ 20 for both genders (sensitivity=.71, specificity=.81, for males; sensitivity=.67, specificity=.69, for females)(p<.05) for acute noncontact lower extremity injuries. Significant positive correlations were found between the FPT composite score and the multi-stage fitness test in male subjects (r=.474, p=.003), suggesting a relationship between functional performance, aerobic capacity, and potential injury risk.A comprehensive assessment of functional performance tests may be beneficial to identify high-injury risk adolescents prior to athletic participation.
Cardiovascular fitness can improve autonomic function (AF) in human immunodeficiency virus (HIV)-infected individuals.Cross-sectional study investigating relationship between AF and cardiovascular fitness in HIV+ individuals on antiretroviral therapy. Participants' (n=29) maximal oxygen consumption (VO2MAX) were assessed by graded exercise test and scaled allometrically, then divided into tertiles by fitness level (Unfit, Low-fit, and Moderately-fit). Heart rate variability (HRV) and the Autonomic Reflex Screen were used to assess AF.Median VO2MAX were 104.9, 130.5, and 150.2 mL•kg-.67•min-1 for Unfit (n=10), Low-fit (n=10), and Moderately-fit (n= 9) groups respectively (p<0.05). Positive correlations were found between VO2MAX and HRV (Spearman's rho range 0.383 to 0.553) were found. Quantitative Sudomotor Axon Reflex Test (QSART) Distal Leg volumes was lower in Unfit compared to Low-fit (p=0.007) and Moderately-fit groups (p=0.018). Unfit QSART total volumes was lower than Moderately-fit (p=0.014).A positive relationship existed between AF and fitness levels. HIV+ individuals could benefit from improved fitness.
