Aubry, RL, Power, GA, and Burr, JF. An assessment of running power as a training metric for elite and recreational runners. J Strength Cond Res 32(8): 2258-2264, 2018-Power, as a testing and training metric to quantify effort, is well accepted in cycling, but is not commonly used in running to quantify effort or performance. This study sought to investigate a novel training tool, the Stryd Running Power Meter, and the applicability of running power (and its individually calculated run mechanics) to be a useful surrogate of metabolic demand (V[Combining Dot Above]O2), across different running surfaces, within different caliber runners. Recreational (n = 13) and elite (n = 11) runners completed a test assessing V[Combining Dot Above]O2 at 3 different paces, while wearing a Stryd Power Meter on both an indoor treadmill and an outdoor track, to investigate relationships between estimated running power and metabolic demand. A weak but significant relationship was found between running power and V[Combining Dot Above]O2 considering all participants as a homogenous group (r = 0.29); however, when assessing each population individually, no significant relationship was found. Examination of the individual mechanical components of power revealed that a correlative decrease in V[Combining Dot Above]O2 representing improved efficiency was associated with decreased ground contact time (r = 0.56), vertical oscillation (r = 0.46), and cadence (r = 0.37) on the treadmill in the recreational group only. Although metabolic demand differed significantly between surfaces at most speeds, run power did not accurately reflect differences in metabolic cost between the 2 surfaces. Running power, calculated via the Stryd Power Meter, is not sufficiently accurate as a surrogate of metabolic demand, particularly in the elite population. However, in a recreational population, this training tool could be useful for feedback on several running dynamics known to influence running economy.

Objective To evaluate the p s ychometric properties of the HIV Disability Questionnaire (HDQ) among people living with HIV (PLHIV) in London, United Kingdom (UK). Methods This is a cross-sectional measurement study. We recruited and administered the self-reported HDQ, seven criterion measures, and a demographic questionnaire with adults living with HIV accessing HIV care. We determined median and interquartile ranges (IQR) for disability presence, severity and episodic scores (range 0–100). We calculated Cronbach’s alpha (α) Kuder-Richardson-20 (KR-20) statistics for disability and episodic scores respectively (internal consistency reliability), smallest detectable change (SDC) for each HDQ severity item and domain (precision), and tested 36 a priori hypotheses assessing correlations between HDQ and criterion scores (construct validity). Results Of N = 243 participants, all were male, median age 40 years, 94% currently taking antiretroviral therapy, and 22% living with ≥2 concurrent health conditions. Median HDQ domain scores ranged from 0 (IQR: 0,7) (difficulties with day-to-day activities domain) to 27 (IQR: 14, 41) (uncertainty domain). Cronbach’s alpha for the HDQ severity scale ranged from 0.85 (95% Confidence Interval (CI): 0.80–0.90) in the cognitive domain to 0.93 (95%CI: 0.91–0.94) in the mental-emotional domain. The KR-20 statistic for the HDQ episodic scale ranged from 0.74 (95%CI: 0.66–0.83) in the cognitive domain to 0.91 (95%CI: 0.89–0.94) in the uncertainty domain. SDC ranged from 7.3–15.0 points on the HDQ severity scale for difficulties with day-to-day activities and cognitive symptoms domains, respectively. The majority of the construct validity hypotheses (n = 30/36, 83%) were confirmed. Conclusions The HDQ possesses internal consistency reliability and construct validity with varied precision when administered to males living with HIV in London, UK. Clinicians and researchers may use the HDQ to measure the nature and extent of disability experienced by PLHIV in the UK, and to inform HIV service provision to address the health-related challenges among PLHIV.

Objectives: To assess measurement properties of the HIV Disability Questionnaire (HDQ) among adults with HIV in the United States. Methods: We administered the HDQ, World Health Organization Disability Assessment Schedule II (WHODAS 2.0), and a demographic questionnaire. For internal consistency reliability, we calculated Cronbach α and Kuder-Richardson-20 (KR-20) statistics for disability and episodic scores, respectively (≥0.80 acceptable). For test–retest reliability, we calculated intraclass correlation coefficients (>0.8 acceptable). For construct validity, we tested 15 a priori hypotheses assessing correlations between HDQ and WHODAS 2.0 scores. Results: Of the 128 participants, the majority were males (68%), median age 51 years, taking antiretroviral therapy (96%). Cronbach α ranged from 0.88 (social inclusion) to 0.93 (uncertainty). The KR-20 ranged from 0.86 (cognitive) to 0.96 (uncertainty). Intraclass correlation coefficients ranged from 0.88 (physical, cognitive, social inclusion) to 0.92 (mental–emotional). Of the 15 hypotheses, 13 (87%) were confirmed. Conclusions: The HDQ demonstrates internal consistency reliability, test–retest reliability, and construct validity when administered to a sample of adults with HIV in the United States.

Purpose Our aim was to examine the impact of a community-based exercise (CBE) intervention on cardiorespiratory fitness, cardiovascular health, strength, flexibility, and physical activity outcomes among adults living with HIV. Methods We conducted a longitudinal intervention study with community-dwelling adults living with HIV in Toronto, Canada. We measured cardiopulmonary fitness (V̇O2peak (primary outcome), heart rate, blood pressure), strength (grip strength, vertical jump, back extension, push-ups, curl ups), flexibility (sit and reach test), and self-reported physical activity bimonthly across three phases. Phase 1 included baseline monitoring (8 months); Phase 2 included the CBE Intervention (6 months): participants were asked to exercise (aerobic, strength, balance and flexibility training) for 90 minutes, 3 times/week, with weekly supervised coaching at a community-based fitness centre; and Phase 3 included follow-up (8 months) where participants were expected to continue with thrice weekly exercise independently. We used segmented regression (adjusted for baseline age and sex) to assess the change in trend (slope) among phases. Our main estimates of effect were the estimated change in slope, relative to baseline values, over the 6 month CBE intervention. Results Of the 108 participants who initiated Phase 1, 80 (74%) started and 67/80 (84%) completed the intervention and 52/67 (77%) completed the study. Most participants were males (87%), with median age of 51 years (interquartile range (IQR): 45, 59). Participants reported a median of 4 concurrent health conditions in addition to HIV (IQR: 2,7). Participants attended a median of 18/25 (72%) weekly supervised sessions. Change in V̇O2peak attributed to the six-month Phase 2 CBE intervention was 0.56 ml/kg/min (95% Confidence Interval (CI): -1.27, 2.39). Significant effects of the intervention were observed for systolic blood pressure (-5.18 mmHg; 95% CI: -9.66, -0.71), push-ups (2.30 additional push-ups; 95% CI: 0.69, 3.91), curl ups (2.89 additional curl ups; 95% CI: 0.61, 5.17), and sit and reach test (1.74 cm; 95% CI: 0.21, 3.28). More participants engaged in self-reported strength (p<0.001) and flexibility (p = 0.02) physical activity at the end of intervention. During Phase 3 follow-up, there was a significant reduction in trend of benefits observed during the intervention phase for systolic blood pressure (1.52 mmHg/month; 95% CI: 0.67, 2.37) and sit and reach test (-0.42 cm/month; 95% CI: -0.68, -0.16). Conclusion Adults living with HIV who engaged in this six-month CBE intervention demonstrated inconclusive results in relation to V̇O2peak, and potential improvements in other outcomes of cardiovascular health, strength, flexibility and self-reported physical activity. Future research should consider features tailored to promote uptake and sustained engagement in independent exercise among adults living with HIV. ClinicalTrials.gov Identifier NCT02794415. https://clinicaltrials.gov/ct2/show/record/NCT02794415.

British Academy for Humanities and Social Sciences. Kelly O'Brien is supported by a Canada Research Chair in Episodic Disability and Rehabilitation. This research was undertaken, in part, thanks to funding from the Canada Research Chairs program. We thank Veronica Murrey (King's College London) for her contributions and integral role in the organization of this Symposium.