ECSS Paris 2023: OP-MH43
INTRODUCTION: Low-volume sprint interval training (LVSIT) has been reported to increase peak oxygen uptake (VO2peak) when performed thrice weekly for six weeks. However, methodological and statistical concerns have been raised that limit previous study findings. We sought to critically reassess the VO2peak response to a six week, thrice-weekly LVSIT intervention using a randomized controlled trial design that was constructed to mitigate bias and augment reporting quality. METHODS: The study protocol was formulated in accordance with CONSORT guidelines and registered prior to participant recruitment on the Open Science Framework (https://osf.io/7mwcj). Utilizing individual participant data from two previous studies conducted in our laboratory, we constructed a generative model of our primary outcome, VO2peak, as a function of group (LVSIT and control), age, sex, height, and body mass. Using these previous data and the model, we then conducted simulation experiments to estimate a required sample size of n=15 per group to achieve 80% power to detect a difference of 1 metabolic equivalent (MET) with a credible interval of ≤1 MET. Forty insufficiently active young adults were initially recruited and randomized; three were lost to follow-up, leaving n=37 (13 males and 24 females; 22±2 yrs) who were assigned to perform either six weeks of LVSIT (n=17) or a non-exercise control condition (n=20). The LVSIT protocol involved 3x20-s ‘all out’ sprints over a 10-min session that otherwise consisted of low-intensity cycling. VO2peak testing was conducted by investigators blinded to participant group allocation and performed in the absence of temporal, verbal, or physiological feedback. VO2peak was measured in duplicate at each time point and not averaged prior to modelling. Data were analyzed using a generative linear mixed-effects regression model that regressed post VO2peak on baseline VO2peak, group allocation, age, sex, height, and body mass with varying effects for participants. All data were analysed by an investigator blinded to group assignment. RESULTS: Bayesian linear mixed-effects modelling and individual response analyses revealed that LVSIT significantly improved absolute (+370±168 mL/min) and relative VO2peak (+5.5±2.4 mL/kg/min), but there were no significant changes in the control group. A clinically meaningful increase in VO2peak of ≥1-MET occurred in 71% of LVSIT participants, with 88% exceeding a 0.5-MET + typical error threshold. CONCLUSION: This study unequivocally demonstrates that a six-week LVSIT protocol significantly improved VO2peak in insufficiently active young adults compared to a non-exercise control group. By implementing a robust design that included pre-registration of the study protocol, concealed allocation assignment, statistical best practices and applied bayesian methods, and open data-sharing, this study addresses prior methodological critiques of similar previous work.
Read CV John RenwickECSS Paris 2023: OP-MH43
INTRODUCTION: Acute physical activity leads to exercise-induced hypoalgesia (EIH). The primary aim of this study was to investigate the effects of two different exercise interventions (low intensity but longer and highly intensive but short) on EIH compared to those of a control session. The secondary aim was to evaluate potential differences in EIH regarding the used body landmarks (muscular and bony/articular). METHODS: 20 male (age: 29.4 ± 3.5 yrs, VO2max: 52.9 ± 6.3 ml/min/kg) participants successfully underwent two exercise sessions on a bicycle ergometer (low intensity: 30 minutes at 60% of the individual anaerobic threshold; highly intensive: 90 second isokinetic all-out) and a control session on separate days in a randomized crossover design. Before (T0), post 1’ (T1), and post 40’ exercise (T2) pain sensitivity was determined via pain pressure thresholds (PPT, N/cm2) unilaterally at the rectus femoris (RF), knee, tibialis anterior (TA), ankle, pectoralis major (PM), and sternum. Lactate, heart rate (HR), and rate of perceived exertion (RPE, 6-20) were documented. RESULTS: Baseline (T0) PPT values were not different between the sessions at any landmark (p > 0.104) indicating no carryover effects. The three-way ANOVA resulted in a significant ‘time’ × ‘landmark’ × ‘intervention’ effect (p = 0.007, η2partial = 0.095). Post hoc analyses revealed that PPT values changed following the highly intensive exercise session with PPT_TA being significantly higher at T1 (88.4 ± 28.2) compared to T0 (78.4.2 ± 24.9, p = 0.023) and T2 (71.8 ± 20.3, p = 0.001). PPT_ankle were significantly higher at T1 (55.9 ± 26.5) compared to T2 (45.9 ± 25.4, p = 0.007) but not to T0 (51.3 ± 23.1, p = 0.519). PPT_RF were significantly higher at T1 (89.3 ± 25.4) compared to T0 (73.3 ± 20.6, p = 0.007) and T2 (74.2 ± 21.8, p = 0.004). PPT_knee were significantly higher at T1 (89.4 ± 31.9) compared to T0 (77.4 ± 27.3, p = 0.045) and T2 (70.6 ± 30.1, p = 0.001). PPT_sternum were not significantly different with values of 44.8 ± 19.1 at T1 compared to 39.3 ± 13.7 at T0 (p = 0.065) and 41.0 ± 17.1 at T2 (p = 0.067). PPT_PM were significantly higher at T1 (41.8 ± 18.2) compared to T0 (33.3 ± 13.8, p = 0.002) and T2 (34.6 ± 15.3, p < 0.001). PPT values were neither different after the low intensity nor after the control session at any landmark. Lactate (low intensity: 1.1 ± 0.2; highly intensive: 7.7 ± 2.6 mmol/L), HR (low intensity: 128.9 ± 13.0; highly intensive: 175.2 ± 13.4 bpm), and RPE (low intensity: 11.6 ± 1.9; highly intensive: 19.6 ± 0.8) were significantly higher following the all-out exercise (p < 0.001). CONCLUSION: Results indicate that a 90’’ all-out exercise induces EIH, whereas a 30’ low intensity exercise does not. This emphasizes the role of exercise intensity, rather than duration, as a key determinant of EIH, shedding light on potential dose-response relationships. EIH effects were observed across muscular and articular landmarks but consistently subsided within 40 minutes.
Read CV Fabian TomschiECSS Paris 2023: OP-MH43
INTRODUCTION: Low back pain is the primary cause of global disability with up to 40% of cases attributed to intervertebral disc degeneration. (1) Cross-sectional studies (2,3) showed running was associated with better magnetic resonance imaging-derived intervertebral disc health, yet no randomised controlled trials have assessed the effect of running. Therefore, we examined the effects of running on intervertebral disc health in adults with chronic low back pain. METHODS: This 12-week parallel (1:1) randomised control trial allocated 40 adults aged 18–45 years (mean [SD] age: 33 [6] years, female: 50%) with non-specific chronic low back pain to a running intervention or waitlist control. The running intervention involved a digitally delivered, progressive run-walk interval exercise intervention (3 days/week, 30 minutes/session). Progression was self-directed by participants and in consultation with an accredited exercise physiologist. Magnetic resonance imaging of spinal levels T11/T12 to L5/S1 was performed at baseline, 6 and 12 weeks. The primary outcome was T2 (ms), an objective assessment of intervertebral disc hydration. Secondary objective outcomes were intervertebral disc: height (mm), height-to-vertebral body ratio, volume (cm3) and nucleus-to-annulus signal intensity ratio. Higher objective values indicate better intervertebral disc health. Lastly, Pfirrmann grade (points) assessed intervertebral disc degeneration, a subjective assessment on a 5-point scale, with lower values indicating better intervertebral disc health. RESULTS: There was no attrition or study-related serious adverse events. Mean (SD) intervention adherence was 70% (20%) and total run distance was 50 (32) km, ranging from 2–110 km over 12 weeks. The intervention improved average lumbar Pfirrmann grade (estimated marginal mean net difference [95%CI]: 0.15 [ 0.25, -0.05] points, P=0.004) and height-to-vertebral body ratio ( 0.01 [0.00, 0.02] mm, P=0.039), yet not T2 (-0.13 [-1.74, 1.48] ms, P=0.873), height (0.00 [-0.13, 0.13] mm, P=0.991), volume (-0.01 [ 0.24, 0.23] cm3, P=0.966), or nucleus-to-annulus signal intensity ratio (0.05 [-0.04, 0.13], P=0.272). CONCLUSION: Running improved some outcomes of intervertebral disc health in adults with non-specific chronic low back pain. Importantly, no deleterious effects or adverse events were observed. To determine if these improvements are sustained, exploring the effect of a longer running intervention warrants investigation, with potential implications for treating intervertebral disc pathology and low back pain. References 1. Mohd et al., Int J Mol Sci. 2022;24(1):208. 2. Belavý et al., Sci Rep. 2017;7(1):1–8. 3. Mitchell et al., PloS One. 2020;15(2):e0229457.
Read CV Claire SamannaECSS Paris 2023: OP-MH43