Effects of Muscular Fatigue on Endurance Athletes During a Backyard Ultra Race: A Pilot Study

Neuromuscular fatigue is a complex phenomenon that occurs during long-duration exercise. A backyard ultra-race requires participants to intermittently run laps (\u3c1hour) for distances that ultimately surpass ultramarathon mileage. Quantifying physiological fatigue during ultramarathon races is difficult due to duration, pace, and terrain; however, vertical jump via force plate analysis is an effective field-based method to quantify neuromuscular fatigue, and may be used to further predict individual race longevity. PURPOSE: The purpose of this study is to measure muscular fatigue utilizing force plate analysis during a back-yard ultra-marathon. METHODS: Twelve participants were recruited from sign-up participation in a local backyard ultramarathon race. Each participant performed maximal effort countermovement jumps on the force plate. Participants were instructed to place hands on hips and perform a maximal effort jump two times with two to three seconds rest between. Jumps were collected at baseline and immediately following completion of each 4.167-mile race loop. Participants completed the race course loops until volitional fatigue or until they could no longer maintain a loop in 60 minutes (failure). Participants who completed a total of four laps were included in the analysis for vertical jump height (VJ) and braking rate of force development (BRFD). A repeated-measures analysis of variance (ANOVA) was performed to determine differences in fatigue from baseline to each subsequent lap. Furthermore, data was separated by sex in order to identify any sex-related differences in fatigue. Alpha level was set at 0.05. RESULTS: Eight female (age= 27.6±14.15y; height=161±7cm; weight= 63.22±9.73kg) and four male (age=36.25±10.2y; height= 174.63±5.64cm; weight= 71.21±5.6kg) volunteer runners were included in this analysis. ANOVA (sex x time) revealed no statistically significant interactions for BRFD and VJ. There were no significant main effects observed in BRFD; however, there was a time main effect for VJ (p\u3c0.05). Across the entire sample population, statistical significance was observed in VJ between the second and fourth time point (p\u3c0.05). Though there were no interactions between sex, female VJ between the second and fourth timepoint reached statistical significance (p\u3c0.05). CONCLUSION: VJ measured via force plate analysis may be a viable option to quantify rates of muscular fatigue during an ultramarathon race. Other extracted variables such as BRFD may not be reliable tools due to the lack of skill in participants. Although current literature provides evidence of sex related differences in fatigue rates, there were no significant findings for sex. Limitations include the sample size and possible variability in training status for some novice runners. Further exploration into the sport of ultra-running is warranted to determine if sex-related differences in fatigue within this population

Total Lean Body Mass and Lower Body Lean Mass Correlation with Vertical Jump in Untrained Women Basketball Players after 8 Weeks of Resistance Training

Basketball is a fast, explosive sport where a high vertical jump (VJ) is extremely beneficial. Research has shown that greater amounts of lean mass have been associated with higher force output, and therefore higher VJ. PURPOSE: The purpose of this study is to examine the correlation of overall total lean body mass percentage (TBLM%) and lower body lean mass percentage (LBLM%) and Body fat percentage (BF%) with VJ in previously untrained collegiate D-III women basketball players. METHODS: Fourteen females (20±1.3 years, 170.68±8.76 cm, T1 BF% 28.68±5.38, T2 27.11±5.12) basketball team participated in this study. Athletes were tested on two different occasions (T1 and T2). Dual-X-Ray Absorptiometry (DXA) body composition scan and standard VJ assessment was performed using a Vertec to determine maximum jump height prior to (T1) and following (T2) 8 weeks of an undulating periodization resistance training program 5 days/week). DXA were further analyzed to determine total body lean mass % (TBLM%) and lower-body lean mass % (LBLM%). Data was analyzed using SPSS using paired samples T-test to detect differences (

Sex-Related Differences in Motor Unit Firing Rates and Action Potential Amplitudes of the First Dorsal Interosseous during High-, but not Low-Intensity Contractions

Despite ample evidence that females are weaker and possess smaller muscle cross-sectional areas (CSAs) compared to males, it remains unclear if there are sex-related differences in the properties of motor units (MU). Eleven males (age=22±3 yrs) and twelve females (age=21±1yrs) performed isometric trapezoid muscle actions at 10% and 70% of maximal voluntary contraction (MVC). Surface electromyography signals were recorded and decomposed into MU action potential (AP) waveforms and firing instances. Average MUAP amplitudes (MUAPAMPS), mean firing rates (MFRs), initial firing rates (IFRs) and recruitment thresholds (RT) were calculated for the 10% MVC while MUAPAMPS, IFRs, and MFRs were regressed against RT for the 70% MVC. Ultrasonography was used to measure CSA of the first dorsal interosseous (FDI). Males had greater CSAs (p0.05) during the 10% MVC. For the 70% MVC, the y-intercepts from the MUAPAMPS vs. RT relationships were greater (p0.05) in the slopes. Therefore, smaller CSAs and weaker MVCs are likely the result of smaller higher-threshold MUs for the females

Observation of Jump Height, Peak Propulsive Force, Braking Force, and Loading Force in Acrobatics and Tumbling Athletes During a Completive Season: Pilot

Acrobatics and tumbling is a women’s sport comprised of 3 different positions: base, top, and tumbler. Each position endures substantial impact on the musculotendinous unit, however, tumblers experience the greatest lower extremity eccentric impact leading to a high injury rate. Consistent athlete monitoring may lead to injury prevention and better insights into training. PURPOSE: The purpose of this study is to pilot observational differences in jump height (JH), peak propulsive force (PPF), peak braking force (PBF), and peak landing force (PLF) during the counter movement jump (CMJ) in acrobatics and tumbling between tumbler and non-tumbler athletes during a competitive season. METHODS: Thirty-three female acrobatics and tumbling athletes volunteered for this study and performed jump testing 3 days per week during their competition season. Data was filtered to include only subjects (n = 15; 19.6 ± 1.0 yrs, 160.7 ± 7.156 cm; 63.5 ± 17.9 kg) ten tumblers (160.12 ± 7.02 cm; 57.5 ± 19.1 kg) and five non-tumblers (162.2 ± 3.27 cm; 71.8 ± 10.0 kg) that had consistent compliance during the six-week period. Participants performed three CMJs using Hawkin Dynamics force plates and software with each CMJ separated by a ten second rest. Data was analyzed using SPSS using a 2X6 (position X time) ANOVA (pRESULTS: No significant main effects for time were found (p=0.95) and there was no significant interaction between time and position (p=0.97). There was a significant main effect for position (p=0.006). Follow up analysis observed significant differences in JH, PPF and PBF (pCONCLUSION: This was a pilot study to observe changes eccentric and concentric loading throughout the competitive season of a DIII acrobatics and tumbling team. When collapsed across time, tumblers experienced greater decline in JH, PPF and PBF throughout the season

Modified Reactive Strength Index in DIII Acrobatics and Tumbling Athletes: A Retrospective Pilot Study

Acrobatics and tumbling is a physically demanding sport that combines skills used in cheerleading and gymnastics during individual and group acrobatic lifts, tosses, and tumbling passes. These athletes experience excessive loading of the lower extremities during training and competition. Due to the explosive demands of the sport, injuries are common. Modified reactive strength index (mRSI) is the ability to change from an eccentric muscle action to a concentric muscle action and has been used as a field-based method to assess recovery and exercise readiness using the countermovement jump (CMJ). PURPOSE: The purpose of this study is to investigate changes in mRSI throughout a competitive season in Division III acrobatics and tumbling athletes which could guide practitioners in the use of force plate and CMJ assessments. METHODS: Thirty-three female acrobatics and tumbling athletes volunteered for this study and performed jump testing 3 days per week during their competition season. Data was filtered to include only subjects (n = 16; 19.6 ± 1.1 yrs, 160.5 ± 6.6 cm; 62.5 ± 18 kg) that had consistent compliance during the six-week period that was analyzed. Participants performed three CMJs using Hawkin Dynamics force plates and software using standardized CMJ procedures with each CMJ separated by a ten-second rest. mRSI (calculated by dividing jump height by ground contact time) and percent change in mRSI were calculated for each respective time point. mRSI and percent change mRSI were analyzed in SPSS using a one-way ANOVA (p\u3c0.05). RESULTS: There were no significant differences in mRSI (p=0.657) or percent change mRSI (p=0.437) throughout all time points. Observed percent changes in mRSI from baseline were -2.88%, -8.25%, -4.75%, -0.45%, and -0.33%. CONCLUSION: These findings indicate that mRSI as a measure of exercise readiness was not statistically changed over time in DIII women’s tumbling and acrobatic athletes. This data can be used by practitioners to better understand the impact of the current practice and training schedule for these athletes. Future work should focus on better consistency in data collection methodology for more extensive timepoint assessment

Effects of Endurance Cycling on Mechanomyographic Median Power Frequency of the Vastus Lateralis

This study examined the effects of cycling training on mechanomyographic median power frequency (MMGMDF)–torque relationships of the vastus lateralis (VL). Ten males (Age ± SD; 20.20 ± 1.87 years) and 14 females (21.93 ± 5.33 years) performed isometric trapezoidal muscle actions with the knee extensors at 40% maximal voluntary contraction (MVC) before (PRE) and following 10 weeks of cycling training at the same absolute submaximal torque as pre-training (POSTABS). MMGMDF–torque relationships (increasing and decreasing segment) were log-transformed and b terms (slopes) were calculated. MMGMDF was averaged during steady torque. For POSTABS, the b terms for the females (0.133 ± 0.190) were greater than for the males (−0.083 ± 0.200; p = 0.013) and compared to PRE (0.008 ± 0.161; p = 0.036). At PRE, the b terms for the linearly increasing-muscle action (0.123 ± 0.192) were greater compared to the linearly decreasing-muscle action (−0.061 ± 0.188; p < 0.001), whereas no differences existed between muscle actions for POSTABS (p > 0.05). In conclusion, 10 weeks of cycling training resulted in different motor unit (MU) control strategies between sexes and altered MU control strategies between muscle actions for the VL during a moderate-intensity contraction

Efficacy and safety of sparsentan versus irbesartan in patients with IgA nephropathy (PROTECT): 2-year results from a randomised, active-controlled, phase 3 trial

BackgroundSparsentan, a novel, non-immunosuppressive, single-molecule, dual endothelin angiotensin receptor antagonist, significantly reduced proteinuria versus irbesartan, an angiotensin II receptor blocker, at 36 weeks (primary endpoint) in patients with immunoglobulin A nephropathy in the phase 3 PROTECT trial's previously reported interim analysis. Here, we report kidney function and outcomes over 110 weeks from the double-blind final analysis.MethodsPROTECT, a double-blind, randomised, active-controlled, phase 3 study, was done across 134 clinical practice sites in 18 countries throughout the Americas, Asia, and Europe. Patients aged 18 years or older with biopsy-proven primary IgA nephropathy and proteinuria of at least 1·0 g per day despite maximised renin–angiotensin system inhibition for at least 12 weeks were randomly assigned (1:1) to receive sparsentan (target dose 400 mg oral sparsentan once daily) or irbesartan (target dose 300 mg oral irbesartan once daily) based on a permuted-block randomisation method. The primary endpoint was proteinuria change between treatment groups at 36 weeks. Secondary endpoints included rate of change (slope) of the estimated glomerular filtration rate (eGFR), changes in proteinuria, a composite of kidney failure (confirmed 40% eGFR reduction, end-stage kidney disease, or all-cause mortality), and safety and tolerability up to 110 weeks from randomisation. Secondary efficacy outcomes were assessed in the full analysis set and safety was assessed in the safety set, both of which were defined as all patients who were randomly assigned and received at least one dose of randomly assigned study drug. This trial is registered with ClinicalTrials.gov, NCT03762850.FindingsBetween Dec 20, 2018, and May 26, 2021, 203 patients were randomly assigned to the sparsentan group and 203 to the irbesartan group. One patient from each group did not receive the study drug and was excluded from the efficacy and safety analyses (282 [70%] of 404 included patients were male and 272 [67%] were White) . Patients in the sparsentan group had a slower rate of eGFR decline than those in the irbesartan group. eGFR chronic 2-year slope (weeks 6–110) was −2·7 mL/min per 1·73 m2 per year versus −3·8 mL/min per 1·73 m2 per year (difference 1·1 mL/min per 1·73 m2 per year, 95% CI 0·1 to 2·1; p=0·037); total 2-year slope (day 1–week 110) was −2·9 mL/min per 1·73 m2 per year versus −3·9 mL/min per 1·73 m2 per year (difference 1·0 mL/min per 1·73 m2 per year, 95% CI −0·03 to 1·94; p=0·058). The significant reduction in proteinuria at 36 weeks with sparsentan was maintained throughout the study period; at 110 weeks, proteinuria, as determined by the change from baseline in urine protein-to-creatinine ratio, was 40% lower in the sparsentan group than in the irbesartan group (−42·8%, 95% CI −49·8 to −35·0, with sparsentan versus −4·4%, −15·8 to 8·7, with irbesartan; geometric least-squares mean ratio 0·60, 95% CI 0·50 to 0·72). The composite kidney failure endpoint was reached by 18 (9%) of 202 patients in the sparsentan group versus 26 (13%) of 202 patients in the irbesartan group (relative risk 0·7, 95% CI 0·4 to 1·2). Treatment-emergent adverse events were well balanced between sparsentan and irbesartan, with no new safety signals.InterpretationOver 110 weeks, treatment with sparsentan versus maximally titrated irbesartan in patients with IgA nephropathy resulted in significant reductions in proteinuria and preservation of kidney function

Sparsentan in patients with IgA nephropathy: a prespecified interim analysis from a randomised, double-blind, active-controlled clinical trial

Background: Sparsentan is a novel, non-immunosuppressive, single-molecule, dual endothelin and angiotensin receptor antagonist being examined in an ongoing phase 3 trial in adults with IgA nephropathy. We report the prespecified interim analysis of the primary proteinuria efficacy endpoint, and safety. Methods: PROTECT is an international, randomised, double-blind, active-controlled study, being conducted in 134 clinical practice sites in 18 countries. The study examines sparsentan versus irbesartan in adults (aged ≥18 years) with biopsy-proven IgA nephropathy and proteinuria of 1·0 g/day or higher despite maximised renin-angiotensin system inhibitor treatment for at least 12 weeks. Participants were randomly assigned in a 1:1 ratio to receive sparsentan 400 mg once daily or irbesartan 300 mg once daily, stratified by estimated glomerular filtration rate at screening (30 to 1·75 g/day). The primary efficacy endpoint was change from baseline to week 36 in urine protein-creatinine ratio based on a 24-h urine sample, assessed using mixed model repeated measures. Treatment-emergent adverse events (TEAEs) were safety endpoints. All endpoints were examined in all participants who received at least one dose of randomised treatment. The study is ongoing and is registered with ClinicalTrials.gov, NCT03762850. Findings: Between Dec 20, 2018, and May 26, 2021, 404 participants were randomly assigned to sparsentan (n=202) or irbesartan (n=202) and received treatment. At week 36, the geometric least squares mean percent change from baseline in urine protein-creatinine ratio was statistically significantly greater in the sparsentan group (-49·8%) than the irbesartan group (-15·1%), resulting in a between-group relative reduction of 41% (least squares mean ratio=0·59; 95% CI 0·51-0·69; p<0·0001). TEAEs with sparsentan were similar to irbesartan. There were no cases of severe oedema, heart failure, hepatotoxicity, or oedema-related discontinuations. Bodyweight changes from baseline were not different between the sparsentan and irbesartan groups. Interpretation: Once-daily treatment with sparsentan produced meaningful reduction in proteinuria compared with irbesartan in adults with IgA nephropathy. Safety of sparsentan was similar to irbesartan. Future analyses after completion of the 2-year double-blind period will show whether these beneficial effects translate into a long-term nephroprotective potential of sparsentan. Funding: Travere Therapeutics

Health-status outcomes with invasive or conservative care in coronary disease

BACKGROUND In the ISCHEMIA trial, an invasive strategy with angiographic assessment and revascularization did not reduce clinical events among patients with stable ischemic heart disease and moderate or severe ischemia. A secondary objective of the trial was to assess angina-related health status among these patients. METHODS We assessed angina-related symptoms, function, and quality of life with the Seattle Angina Questionnaire (SAQ) at randomization, at months 1.5, 3, and 6, and every 6 months thereafter in participants who had been randomly assigned to an invasive treatment strategy (2295 participants) or a conservative strategy (2322). Mixed-effects cumulative probability models within a Bayesian framework were used to estimate differences between the treatment groups. The primary outcome of this health-status analysis was the SAQ summary score (scores range from 0 to 100, with higher scores indicating better health status). All analyses were performed in the overall population and according to baseline angina frequency. RESULTS At baseline, 35% of patients reported having no angina in the previous month. SAQ summary scores increased in both treatment groups, with increases at 3, 12, and 36 months that were 4.1 points (95% credible interval, 3.2 to 5.0), 4.2 points (95% credible interval, 3.3 to 5.1), and 2.9 points (95% credible interval, 2.2 to 3.7) higher with the invasive strategy than with the conservative strategy. Differences were larger among participants who had more frequent angina at baseline (8.5 vs. 0.1 points at 3 months and 5.3 vs. 1.2 points at 36 months among participants with daily or weekly angina as compared with no angina). CONCLUSIONS In the overall trial population with moderate or severe ischemia, which included 35% of participants without angina at baseline, patients randomly assigned to the invasive strategy had greater improvement in angina-related health status than those assigned to the conservative strategy. The modest mean differences favoring the invasive strategy in the overall group reflected minimal differences among asymptomatic patients and larger differences among patients who had had angina at baseline