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TaeYeong Kim, JaeHyuk Lee, SeJun Oh, Seungmin Kim and BumChul Yoon

Context: A simulated horseback riding (SHR) exercise is effective for improvement of pain and functional disability, but its comparative effectiveness with the other is unknown. Objective: The authors aimed to demonstrate the effect of a SHR exercise in people with chronic low back pain. Design: A randomized controlled trial. Settings: Community and university campus. Participants: A total of 48 participants with chronic low back pain were divided into 2 groups, and SHR exercises (n = 24) or stabilization (STB) exercises (n = 24) were performed. Interventions: The exercises were performed for 30 minutes, 2 days per week for 8 weeks. Main Outcome Measures: Numeric rating scale, functional disabilities (Oswestry disability index and Roland–Morris disability), and fear-avoidance beliefs questionnaire (FABQ) scores were measured at baseline and at 4 weeks, 8 weeks, and 6 months. Results: A 2-way repeated analysis of variance identified that between-group comparisons showed significant differences in the FABQ related to work scale (F = 21.422; P = .01). There were no significant differences in the numeric rating scale (F = 1.696; P = .21), Oswestry disability index (F = 1.848; P = .20), Roland–Morris disability (F = 0.069; P = .80), and FABQ related to physical scale (F = 1.579; P = .24). In within-group comparisons, both groups presented significant differences in numeric rating scale (both SHR and STB after 4 wk), Oswestry disability index (both SHR and STB after 6 mo), and Roland–Morris disability (SHR after 6 mo and STB after 8 wk) compared with baseline values. In FABQ-related physical (SHR after 4 wk) and work scales (SHR after 6 mo), there were only significant differences in the SHR compared with baseline values. Conclusions: SHR exercise for 8 weeks had a greater effect than STB exercise for reducing work-related FABQ. The SHR exercise performed in a seated position could substantially decrease pain-related fear disability in young adults with chronic low back pain.

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Jonathon Weakley, Carlos Ramirez-Lopez, Shaun McLaren, Nick Dalton-Barron, Dan Weaving, Ben Jones, Kevin Till and Harry Banyard

Purpose: Prescribing resistance training using velocity loss thresholds can enhance exercise quality by mitigating neuromuscular fatigue. As little is known regarding performance during these protocols, we aimed to assess the effects of 10%, 20%, and 30% velocity loss thresholds on kinetic, kinematic, and repetition characteristics in the free-weight back squat. Methods: Using a randomized crossover design, 16 resistance-trained men were recruited to complete 5 sets of the barbell back squat. Lifting load corresponded to a mean concentric velocity (MV) of ∼0.70 m·s−1 (115 [22] kg). Repetitions were performed until a 10%, 20%, or 30% MV loss was attained. Results: Set MV and power output were substantially higher in the 10% protocol (0.66 m·s−1 and 1341 W, respectively), followed by the 20% (0.62 m·s−1 and 1246 W) and 30% protocols (0.59 m·s−1 and 1179 W). There were no substantial changes in MV (−0.01 to −0.02 m·s−1) or power output (−14 to −55 W) across the 5 sets for all protocols, and individual differences in these changes were typically trivial to small. Mean set repetitions were substantially higher in the 30% protocol (7.8), followed by the 20% (6.4) and 10% protocols (4.2). There were small to moderate reductions in repetitions across the 5 sets during all protocols (−39%, −31%, −19%, respectively), and individual differences in these changes were small to very large. Conclusions: Velocity training prescription maintains kinetic and kinematic output across multiple sets of the back squat, with repetition ranges being highly variable. Our findings, therefore, challenge traditional resistance training paradigms (repetition based) and add support to a velocity-based approach.

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Sabrine N. Costa, Edgar R. Vieira and Paulo C. B. Bento

The aims of this study were to compare the effects of a multicomponent exercise program provided at a center (CB) versus done part at home and part at a center (H+CB) on frailty status, strength, physical function, and gait of prefrail older women. Twenty-five women were randomly allocated into the CB (n = 14; 69 ± 6 years) and the H+CB (n = 11; 69 ± 7 years) groups. Both groups completed an exercise program including strengthening, balance, and gait exercises. The program was 12 weeks long, done three times per week, for 60 min per session. Frailty, knee and hip muscle strength, spatiotemporal parameters of the usual and maximum speed dual-task gait, and physical function were assessed at baseline and after program completion. The exercise program reversed the prefrail status of most participants independently of the mode of delivery. Strength increased in both groups, but the CB group had more pronounced improvements in gait and physical function. H+CB exercise programs are good options for prefrail older women.

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Cristiane B.B. Antonelli, Charlini S. Hartz, Sileno da Silva Santos and Marlene A. Moreno

Purpose: To evaluate the effects of inspiratory muscle training associated with interval training on respiratory muscle strength and fatigue and aerobic physical performance (PP) in high-performance wheelchair basketball athletes. Methods: Blinded, randomized clinical trial with 17 male wheelchair basketball players, randomized into control group (CG; n = 8) and training group (TG; n = 9). Respiratory muscle strength was evaluated by measuring maximal inspiratory and expiratory pressures (MIP and MEP), aerobic PP by the Yo-Yo test for wheelchair, and recovery of inspiratory muscle fatigue was assessed at 1, 5, 10, and 15 minutes after exercise test. TG performed inspiratory muscle training protocol with incremental loading for 12 weeks with 50%, 60%, and 70% of MIP, while CG performed with load 15% of MIP. Results: After training period, CG presented a significant increase in MIP and MEP (P ≤ .05), with no change in aerobic PP (P ≥ .05). TG showed a significant increase for all variables (≤.05). MIP showed a large effect size for CG (1.00) and TG (1.35), while MEP showed a moderate effect for CG (0.61) and TG (0.73); distance covered had a moderate effect size for TG (0.70). For recovery of inspiratory muscle strength, CG did not present differences, while TG recovered in 10 minutes (≤.05), representing 87% of the pretest value. Positive and significant correlation between MIP and distance (.54; P ≤ .05) was observed. Conclusion: Inspiratory muscle training protocol with progressive loading was more effective for increasing aerobic PP and maximal inspiratory strength recovery.

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João Ribeiro, Luís Teixeira, Rui Lemos, Anderson S. Teixeira, Vitor Moreira, Pedro Silva and Fábio Y. Nakamura

Purpose : The current study aimed to compare the effects of plyometric (PT) versus optimum power load (OPL) training on physical performance of young high-level soccer players. Methods : Athletes were randomly divided into PT (horizontal and vertical drills) and OPL (squat + hip thrust exercises at the load of maximum power output) interventions, applied over 7 weeks during the in-season period. Squat and countermovement jumps, maximal sprint (10 and 30 m), and change of direction (COD; agility t test) were the pretraining and posttraining measured performance variables. Magnitude-based inference was used for within- and between-group comparisons. Results : OPL training induced moderate improvements in vertical squat jump (effect size [ES]: 0.97; 90% confidence interval [CI], 0.32–1.61) and countermovement jump (ES: 1.02; 90% CI, 0.46–1.57), 30-m sprint speed (ES: 1.02; 90% CI, 0.09–1.95), and COD performance (ES: 0.93; 90% CI, 0.50–1.36). After PT training method, vertical squat jump (ES: 1.08; 90% CI, 0.66–1.51) and countermovement jump (ES: 0.62; 90% CI, 0.18–1.06) were moderately increased, while small enhancements were noticed for 30-m sprint speed (ES: 0.21; 90% CI, −0.02 to 0.45) and COD performance (ES: 0.53; 90% CI, 0.24–0.81). The 10-m sprint speed possibly increased after PT intervention (small ES: 0.25; 90% CI, −0.05 to 0.54), but no substantial change (small ES: 0.36; 90% CI, −0.40 to 1.13) was noticed in OPL. For between-group analyses, the COD ability and 30-m sprint performances were possibly (small ES: 0.30; 90% CI, −0.20 to 0.81; Δ = +1.88%) and likely (moderate ES: 0.81; 90% CI, −0.16 to 1.78; Δ = +2.38%) more improved in the OPL than in the PT intervention, respectively. Conclusions : The 2 different training programs improved physical performance outcomes during the in-season period. However, the combination of vertically and horizontally based training exercises (squat + hip thrust) at optimum power zone led to superior gains in COD and 30-m linear sprint performances.

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Rob van der Straaten, Oren Tirosh, William A. (Tony) Sparrow and Rezaul Begg

Minimum toe clearance (MTC ∼10–30 mm) is a hazardous mid-swing gait event, characterized by high-foot velocity (∼4.60 m·s−1) and single-foot support. This experiment tested treadmill-based gait training effects on MTC. Participants were 10 young (4 males and 6 females) and 10 older (6 males and 4 females) healthy ambulant individuals. The mean age, stature, and body mass for the younger group was 23 (2) years, 1.72 (0.10) m, and 67.5 (8.3) kg, and for older adults was 77 (9) years, 1.64 (0.10) m, and 71.1 (12.2) kg. Ten minutes of preferred speed treadmill walking (baseline) was followed by 20 minutes with MTC information (feedback) and 10 minutes without feedback (retention). There were no aging effects on MTC in baseline or feedback. The MTC in baseline for older adults was 14.2 (3.5) mm and feedback 27.5 (8.7) mm, and for the younger group, baseline was 12.7 (2.6) mm and feedback 28.8 (5.1) mm, respectively. Retention MTC was significantly higher for both groups, indicating a positive effect of augmented information: younger 40.8 (7.3) mm and older 27.7 (13.6) mm. Retention joint angles relative to baseline indicated that the young modulated joint angles control MTC differently using increased ankle dorsiflexion at toe off and modulating knee and hip angles later in swing closer to MTC.

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Arthur H. Bossi, Wouter P. Timmerman and James G. Hopker

Purpose: There are several published equations to calculate energy expenditure (EE) from gas exchanges. The authors assessed whether using different EE equations would affect gross efficiency (GE) estimates and their reliability. Methods: Eleven male and 3 female cyclists (age 33 [10] y; height: 178 [11] cm; body mass: 76.0 [15.1] kg; maximal oxygen uptake: 51.4 [5.1] mL·kg−1·min−1; peak power output: 4.69 [0.45] W·kg−1) completed 5 visits to the laboratory on separate occasions. In the first visit, participants completed a maximal ramp test to characterize their physiological profile. In visits 2 to 5, participants performed 4 identical submaximal exercise trials to assess GE and its reliability. Each trial included three 7-minute bouts at 60%, 70%, and 80% of the gas exchange threshold. EE was calculated with 4 equations by Péronnet and Massicotte, Lusk, Brouwer, and Garby and Astrup. Results: All 4 EE equations produced GE estimates that differed from each other (all P < .001). Reliability parameters were only affected when the typical error was expressed in absolute GE units, suggesting a negligible effect—related to the magnitude of GE produced by each EE equation. The mean coefficient of variation for GE across different exercise intensities and calculation methods was 4.2%. Conclusions: Although changing the EE equation does not affect GE reliability, exercise scientists and coaches should be aware that different EE equations produce different GE estimates. Researchers are advised to share their raw data to allow for GE recalculation, enabling comparison between previous and future studies.

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Matheus Barbalho, Victor S. Coswig, James Steele, James P. Fisher, Jurgen Giessing and Paulo Gentil

Purpose: To compare the effects of different resistance training volumes on muscle performance and hypertrophy in trained men. Methods: Thirty-seven volunteers performed resistance training for 24 weeks, divided into groups that performed 5 (G5), 10 (G10), 15 (G15), and 20 (G20) sets per muscle group per week. Ten-repetition maximum (10RM) tests were performed for the bench press, lat pulldown, 45° leg press, and stiff-legged deadlift. Muscle thickness was measured using ultrasound at biceps brachii, triceps brachii, pectoralis major, quadriceps femoris, and gluteus maximus. All measurements were performed at the beginning (pre), 12 (mid), and 24 weeks (post) of training. Results: All groups showed significant increases in all 10RM tests and muscle thickness measures after 12 and 24 weeks when compared with pre (P < .05). There were no significant differences in any 10RM test or changes between G5 and G10 after 12 and 24 weeks. G5 and G10 showed significantly greater increases for 10RM than G15 and G20 for most exercises at 12 and 24 weeks. There was no group by time interaction for any muscle thickness measure. Conclusions: The results bring evidence of an inverted “U-shaped” curve for the dose–response curve for muscle strength. Although the same trend was noted for muscle hypertrophy, the results did not reach significance. Five to 10 sets per week might be sufficient for bringing about optimal gains in muscle size and strength in trained men over a 24-week period.