Abstract Vatne, EA, Cencer, D, Vatne, M, Pulvermacher, K, Saenz, C, Kraemer, WJ, Robinson, B, Jones, P, Quebedeaux, N, Sprague, R, Dial, M, Carpenter, T, and Hagen, J. Relationship between objective measures of sleep and nocturnal cardiovascular physiology and swimming performance in collegiate female athletes: A Bayesian analysis. J Strength Cond Res XX(X): 000–000, 2026—There is substantial evidence that sleep influences athletic performance; however, relationships with real-world competition outcomes remain unclear. Therefore, the purpose of this study was to explore the associations between objectively measured sleep, nocturnal cardiovascular physiology on the night before competition, and swim performance in female collegiate athletes. Female swimmers ( n = 11) who wore a sleep monitoring device the night before competition, competed in the 200-yard freestyle (short course yard), and had ≥21 of 28 prior nights of valid data were included. Sleep metrics included total sleep time (TST), time in bed (TiB), and sleep efficiency (SE), whereas nocturnal cardiovascular metrics included heart rate variability (HRV) and resting heart rate (RHR) standardized as individualized z -scores. Race times were obtained from a publicly available database. Bayesian linear mixed-effects models estimated posterior probabilities of performance improvement. Results indicated a high probability that greater TST and TiB were associated with faster race times, with substantial support for improvements of at least 1 second per additional hour of sleep. In contrast, SE, HRV, and RHR showed low posterior evidence of meaningful associations with performance. These findings extend prior sleep and performance literature that has been confined to proxy assessments of athletic performance in controlled settings to real-world competition that should inform athlete education, emphasizing the importance of sufficient sleep opportunity and duration before competition.
Abstract Lang, D, Fallo, X, and Bennett, H. An automated blood flow restriction device is reliable, but not valid, for determining lower limb occlusion pressure in resistance-trained adults. J Strength Cond Res XX(X): 000–000, 2026—Blood flow restriction (BFR) exercise can improve strength, hypertrophy, and aerobic performance. Accurate limb occlusion pressure (LOP) assessment is essential for safe prescription. The AirBands is a novel automated BFR device that estimates LOP using integrated sensors, making LOP assessment easier. However, its validity and reliability are not well established in resistance-trained individuals. This study evaluated the concurrent validity of the AirBands compared with a handheld Doppler ultrasound for lower limb LOP, and its test-retest reliability, in resistance-trained adults. Twenty-six resistance-trained adults (14 males, 12 females; 24.2 ± 4.7 years) participated. For validity, LOP was measured using AirBands and Doppler in randomized order, using the same cuff. For reliability, automated LOP was measured twice, 10 minutes apart. Agreement was assessed using Bland-Altman limits of agreement and intraclass correlation coefficients (ICC). No significant difference was observed between manual (231.7 ± 17.8 mm Hg) and automated (230.8 ± 38.3 mm Hg) LOP (mean difference −0.8 mm Hg; p = 0.928), although validity ICC was poor (0.236, 95% confidence interval [CI] = −0.293 to 0.641). Bland-Altman analysis indicated proportional bias, with overestimation at lower values and underestimation at higher values. Reliability showed no significant difference between test 1 (243.0 ± 37.5 mm Hg) and test 2 (242.3 ± 40.5 mm Hg) (mean difference 1.0 mm Hg; p = 0.816) and good reliability (ICC = 0.862, 95% CI = 0.715 to 0.936). AirBands demonstrates good test-retest reliability but poor concurrent validity vs. Doppler ultrasound. Clinicians should confirm automated values using a Doppler ultrasound before prescribing BFR.
Abstract Yan, X, Zuo, Z, Nitsche, MA, Zhang, X, and Qi, F. Multiple sessions of transcranial direct current stimulation combined with squat training improve lower-limb maximum strength in healthy adult men. J Strength Cond Res XX(X): 000–000, 2026—This study aimed to investigate the effects of transcranial direct current stimulation (tDCS) combined with Squat training (ST) on lower-limb maximum strength in healthy adult men. Sixty men (age: 21.6 ± 2.1 years, height: 177.5 ± 5.3 cm, body mass: 73.1 ± 7.4 kg) were randomly assigned to 4 groups (tDCS + ST group, sham tDCS + ST group, tDCS + rest group, sham tDCS + rest group). The 6-week intervention program was implemented with biweekly sessions, totaling 12 treatment sessions, each separated by a minimum 48-hour interval. After the tDCS intervention, the ST groups performed squat exercises while the tDCS + rest and sham tDCS + rest groups sat quietly for 30 minutes. Lower-limb maximal muscle strength was measured at 4 distinct time points: preintervention (T0), 24 hours post-third week intervention (T1), 24 hours post-sixth week final session (T2), and 1 week post-entire intervention completion (T3). Key evaluation metrics were measured, including 1 repetition maximum (1RM) squat, knee extensor and flexor peak torque, and rectus femoris cross-sectional area (CSA). Significant improvements in 1RM, knee extensor strength, and nondominant rectus femoris CSA were observed in both tDCS + ST and sham tDCS + ST groups compared with the sham tDCS-only group ( p < 0.05). No differences in knee strength, 1RM, or rectus femoris CSA were observed between the tDCS + rest and sham tDCS + rest groups. The results indicate that anodal tDCS combined with ST does not yield additional training benefits on lower-limb maximal strength in healthy adults when compared with ST alone.
Abstract Rebelo, A, Ripley, N, Weakley, J, and Comfort, P. Relationships between isometric belt squat force and vertical jump performance across knee joint angles. J Strength Cond Res XX(X): 000–000, 2026—The aim of this study was to examine the relationships between vertical jump performance and isometric belt squat force assessed at 2 knee joint angles (120° and 90°) and to compare outcomes across age groups in male and female athletes. One hundred and twenty subjects (20.3 ± 6.5 years, 1.77 ± 0.12 m, 71.0 ± 13.3 kg) performed countermovement jumps, squat jumps, and isometric belt squat tests at 120° and 90° on dual force platforms. Between-group differences were analyzed using 1-way or Welch's analysis of variance with Bonferroni-adjusted post hoc analyses. Associations were examined using Pearson's correlations with Bonferroni-adjusted significance thresholds ( p < 0.002), while omnibus tests used corrected alpha levels where applicable. Isometric belt squat net peak force demonstrated weak-to-moderate associations with jump height across tasks ( r = 0.36–0.55). Associations between net force at 200 milliseconds and jump height were moderate at 90° ( r = 0.45–0.52), whereas net force at 100 milliseconds showed negligible associations to jump height. Older athletes produced significantly higher absolute isometric net peak force than younger groups only at 90° knee flexion (up to ∼860 N difference), with moderate-to-large effects ( g = 0.67–0.80), whereas relative net peak force did not differ between age categories. These findings indicate that the isometric belt squat can be confidently used to monitor maximal lower-limb force capacity across knee angles, with the 90° position offering greater sensitivity for distinguishing strength levels between age groups.
Abstract Mitchinson, CJ, Benitez, B, Kwak, M, Snell, E, Kuhn, AN, and Bergstrom, HC. Effects of target heart rate attainment method on metabolic, perceptual, and performance responses during heart rate-clamp exercise in recreationally active female subjects. J Strength Cond Res XX(X): 000–000, 2026—This study used a test-retest design to examine ramp and immediate protocols for attaining a target heart rate (HR) and the subsequent effects on metabolic, respiratory, perceptual, and performance responses during HR-clamp cycle ergometry. Fifteen recreationally active female subjects (22 ± 5 years) completed a graded exercise test to determine maximal oxygen consumption (V̇O 2 max) and maximal HR (HRmax), followed by 4 randomized, 20-minute HR-clamp trials at 86% HRmax using either a ramp (gradual increases in power output [PO]) or immediate (instantaneous application of target PO) protocol, each performed twice. Oxygen consumption (V̇O 2 ), minute ventilation (V̇ E ), respiration rate (RR), rating of perceived exertion (RPE), PO, and time to target HR were assessed at HR attainment and averaged across the HR-clamp trials. Analyses included linear mixed models fitted with fixed effects and random intercepts, and one-way repeated measures ANOVAs with intraclass correlation coefficients to examine test-retest reliability ( p < 0.05). Time to target HR did not differ between protocols ( p = 0.958). However, the ramp protocol elicited a greater V̇O 2 , RR, V̇ E , and PO at HR attainment ( p < 0.001–0.035) and a greater V̇O 2 and PO across the HR-clamp trials ( p = 0.008–0.017) compared with the immediate protocol, whereas RPE did not differ between protocols ( p = 0.118–0.984). The ramp protocol demonstrated greater systematic error for metabolic and performance measures, whereas the immediate protocol showed less systematic error and comparable reliability. These findings indicated that the method used to attain a target HR significantly alters the physiological stimulus of HR-clamp exercise, and practitioners and researchers should carefully consider protocol selection when prescribing or interpreting HR-clamp exercise.
