Purpose: To determine the acute effects of carbohydrate (CHO) ingestion following a bout of maximal eccentric resistance exercise on key anabolic kinases of mammalian target of rapamycin and extracellular signal-regulated kinase (ERK) pathways. The authors’ hypothesis was that the activation of anabolic signaling pathways known to be upregulated by resistance exercise would be further stimulated by the physiological hyperinsulinemia resulting from CHO supplementation. Methods: Ten resistance-trained men were randomized in a crossover, double-blind, placebo (PLA)-controlled manner to ingest either a noncaloric PLA or 3 g/kg of CHO beverage throughout recovery from resistance exercise. Muscle biopsies were collected at rest, immediately after a single bout of intense lower body resistance exercise, and after 3 hr of recovery. Results: CHO ingestion elevated plasma glucose and insulin concentrations throughout recovery compared with PLA ingestion. The ERK pathway (phosphorylation of ERK1/2 [Thr202/Tyr204], RSK [Ser380], and p70S6K [Thr421/Ser424]) was markedly activated immediately after resistance exercise, without any effect of CHO supplementation. The phosphorylation state of AKT (Thr308) was unchanged postexercise in the PLA trial and increased at 3 hr of recovery above resting with ingestion of CHO compared with PLA. Despite stimulating-marked phosphorylation of AKT, CHO ingestion did not enhance resistance exercise–induced phosphorylation of p70S6K (Thr389) and rpS6 (Ser235/236 and Ser240/244). Conclusion: CHO supplementation after resistance exercise and hyperinsulinemia does not influence the ERK pathway nor the mTORC1 target p70S6K and its downstream proteins, despite the increased AKT phosphorylation.
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Vandre C. Figueiredo, Michelle M. Farnfield, Megan L.R. Ross, Petra Gran, Shona L. Halson, Jonathan M. Peake, David Cameron-Smith and James F. Markworth
Jason R. Boynton, Fabian Danner, Paolo Menaspà, Jeremiah J. Peiffer and Chris R. Abbiss
Purpose: To examine the effect of environmental temperature (T A) on performance and physiological responses (eg, body temperature, cardiopulmonary measures) during a high-intensity aerobic interval session. It was hypothesized that power output would be highest in the 13°C condition and lower in the 5°C, 22°C, and 35°C conditions. Methods: Eleven well-trained cyclists randomly completed 4 interval sessions at 5°C, 13°C, 22°C, and 35°C (55% [13%] relative humidity), each involving five 4-min intervals interspersed with 5 min of recovery. During the intervals, power output, core temperature (T C), skin temperature, VO2, and heart rate were recorded. Results: Mean session power output for 13°C (366  W) was not higher than 5°C (363  W; P = 1.00, effect size = 0.085), 22°C (364  W; P = 1.00, effect size = 0.061), or 35°C (352  W; P = .129, effect size = 0.441). The 5th interval of the 35°C condition had a lower power output compared with all other T A. T C was higher in 22°C compared with both 5°C and 13°C (P = .001). VO2 was not significantly different across T A (P = .187). Heart rate was higher in the 4th and 5th intervals of 35°C compared with 5°C and 13°C. Conclusions: This study demonstrates that while mean power outputs for intervals are similar across T A, hot T A (≥35°C) reduces interval power output later in a training session. Well-trained cyclists performing maximal high-intensity aerobic intervals can achieve near-optimal power output over a broader range of T A than previous literature would indicate.
Ali Jalalvand and Mehrdad Anbarian
Context: The link between landing parameters and lower limb muscle fatigue in association with chronic low back pain (CLBP) is not well understood. Objective: To examine the effects of fatigue on the ground reaction force components during landing in people with nonspecific CLBP. Design: Quasi-experimental study. Setting: Clinical biomechanics laboratory. Participants: A total of 44 subjects were equally divided into a healthy group and a group with CLBP. Main Outcome Measures: The ground reaction force along anterior–posterior (y) and medial–lateral (x) and vertical (z) axes, time to peak (TTP), the rate of force development, and impulses for all axes were calculated. A repeated-measures analysis of variance (group × fatigue) was used to compare the data among groups. Results: In the unfatigued conditions, the amplitudes of Fy3, Fz2, and TTP of Fy1, Fy2, Fz1, Fz2, Fz3, Fz4, rate of force development in Y in the CLBP subjects are significantly different than those in the healthy subjects (P < .05). In the fatigued conditions, the amplitudes of Fz2, Fz3, Fz4, and TTP of Fy2, Fy3, Fy4, Fz2, impulses of X 2, Z in the CLBP group were significantly different than those in the healthy subjects (P < .05). Within-group comparisons of measured Fx1, Fy1, Fy2, Fz2, Fz4 and TTP of Fx1, Fy1, Fy2, Fz2, Fz3, Fz4, impulses of X 2, z were significantly different from prefatigue to postfatigue in the healthy group (P < .05). Within-group comparisons of measured Fx1, Fy1, Fz1, Fz2 and TTP of Fx5, Fz1, impulses of X2 were significantly differed from prefatigue to postfatigue in the CLBP group (P < .05). Conclusions: It seems that TTP of ground reaction force variables in CLBP may have clinical values for rehabilitation. Muscle fatigue altered landing performance. However, patients with CLBP will respond differently to lower-extremity fatigue. These altered variables in patients with low back pain are the cause of future injuries or lower-extremity injuries that need to be addressed in further studies.
Ji-Hyun Lee and Tae-Lim Yoon
Context: Kinesiology tape (KT), multidirectional resistance exercise, and interventions for decreased ankle dorsiflexion range of motion are gaining popularity in the treatment of patients with chronic ankle instability (CAI). However, there is limited evidence of the effectiveness of combined interventions in patients with CAI. Objectives: To compare the effects of KT alone, KT with resistance exercise (KT + resistance), and KT with resistance and heel raise-lower exercise (KT + resistance + heel) on the results of the dynamic balance test (star excursion balance test [SEBT]), functional performance (lateral step-down test), and ankle muscle activation in patients with CAI. Design and Setting: This study used a repeated-measures design in a laboratory setting. Main Outcome Measures: The participants completed 3 different interventions with a 24-hour rest period between interventions. The SEBT, lateral step-down test, and ankle muscle activation results were used as the outcome measures. All outcomes were assessed before and immediately after the 3 interventions. Results: The results of the SEBT-anteromedial direction significantly increased with KT + resistance (78.61 [16.11] cm, P = .01, ES = 0.50) and KT + resistance + heel (76.94 [16.00] cm, P = .03, ES = 0.33) in comparison with the baseline values (73.68 [12.84] cm). Additionally, the result of the SEBT-anteromedial direction was significantly greater with KT + resistance (78.61 [16.11] cm) than with KT alone (76.00 [14.90] cm, P = .05, ES = 0.18). The number of errors during the lateral step-down test was significantly lower for the KT alone (2.16 [0.90] errors, P = .02, ES = 0.46), KT + resistance (2.10 [0.79] errors, P = .01, ES = 0.54), and KT + resistance + heel (2.03 [0.75] errors, P = .003, ES = 0.61) interventions than the baseline values (2.55 [0.85] errors). Conclusions: Patients with CAI should be encouraged to perform KT + resistance to improve balance.
Matt Hausmann, Jacob Ober and Adam S. Lepley
Clinical Scenario: Ankle sprains are the most prevalent athletic-related musculoskeletal injury treated by athletic trainers, often affecting activities of daily living and delaying return to play. Most of these cases present with pain and swelling in the ankle, resulting in decreased range of motion and strength deficits. Due to these impairments, proper treatment is necessary to avoid additional loss of play and prevent future injuries. Recently, there has been an increased use of deep oscillation therapy by clinicians to manage pain and swelling following a variety of injuries, including ankle sprains. However, very little evidence has been produced regarding the clinical effectiveness of deep oscillation therapy, limiting its application in therapeutic rehabilitation of acute lateral ankle sprains. Clinical Question: Is deep oscillation therapy effective in reducing pain and swelling in patients with acute lateral ankle sprains compared with the current standard of care protection, rest, ice, compression, and elevation? Summary of Key Findings: The literature was searched for studies of level 2 evidence or higher that investigated deep oscillation therapy on pain and inflammation in patients with lateral ankle sprains. Three randomized control trials were located and appraised. One of the 3 studies demonstrate a reduction in pain following 6 weeks of deep oscillation therapy compared with the standard of care or placebo interventions. The 2 other studies, 1 utilizing a 5-day treatment and the other a 1 time immediate application, found no differences in deep oscillation therapy compared with the standard of care. Clinical Bottom Line: There is inconclusive evidence to support the therapeutic use of deep oscillation therapy in reducing pain and swelling in patients with acute lateral ankle sprains above and beyond the current standard of care. In addition, the method of treatment application and parameters used may influence the effectiveness of deep oscillation therapy. Strength of Recommendation: Level B.
Rachel Massie, James Smallcombe and Keith Tolfrey
Purpose: Chronic exercise programs can induce adaptive compensatory behavioral responses through increased energy intake (EI) and/or decreased free-living physical activity in adults. These responses can negate the benefits of an exercise-induced energy deficit; however, it is unclear whether young people experience similar responses. This study examined whether exercise-induced compensation occurs in adolescent girls. Methods: Twenty-three adolescent girls, heterogeneous for weight status, completed the study. Eleven adolescent girls aged 13 years completed a 12-week supervised exercise intervention (EX). Twelve body size–matched girls comprised the nonexercise control group (CON). Body composition, EI, free-living energy expenditure (EE), and peak oxygen uptake (
Mehrez Hammami, Rodrigo Ramirez-Campillo, Nawel Gaamouri, Gaith Aloui, Roy J. Shephard and Mohamed Souhaiel Chelly
Purpose: To analyze the effects of a 9-week plyometric training program on the sprint times (5, 10, 20, and 30 m), change-of-direction speed (modified T test and modified Illinois test), jumping (squat jump, countermovement jump, countermovement jump with arms, and horizontal 5-jump test), upper-body strength (right and left handgrip, back extensor strength, and medicine ball throw), and balance (Y and stork balance tests) of female handball players. Methods: Athletes were randomly divided into experimental (n = 21; age = 13.5 [0.3] y) and control (n = 20; age = 13.3 [0.3] y) groups. Training exercises and matches were performed together, but the experimental group replaced a part of their normal regimen by biweekly upper- and lower-limb plyometric training. Results: Both groups improved performance, but to a greater extent in the experimental group compared with controls for 20- and 30-m sprint times (Δ% = 9.6, P < .05, d = 0.557 and Δ% = 20.9, P < .001, d = 1.07, respectively), change of direction (T test: P < .01, Δ% = 14.5, d = 0.993 and Illinois test: P < .01, Δ% = 7.9, d = 0.769), vertical and horizontal jumping (P < .05), all measures of upper-limb strength (P < .001), and left-leg stork balance (P < .001, Δ% = 49.9, d = 1.07). Conclusions: A plyometric training program allows female junior handball players to improve important components of their physical performance.
Robyn F. Madden, Kelly A. Erdman, Jane Shearer, Lawrence L. Spriet, Reed Ferber, Ash T. Kolstad, Jessica L. Bigg, Alexander S.D. Gamble and Lauren C. Benson
Purpose: To determine the effects of low-dose caffeine supplementation (3 mg/kg body mass) consumed 1 h before the experiment on rating of perceived exertion (RPE), skills performance (SP), and physicality in male college ice hockey players. Methods: Using a double-blind, placebo-controlled, randomized crossover experimental design, 15 college ice hockey players participated in SP trials and 14 participated in scrimmage (SC) trials on a total of 4 d, with prescribed ice hockey tasks occurring after a 1-h high-intensity practice. In the SP trials, time to complete and error rate for each drill of the validated Western Hockey League Combines Testing Standard were recorded. Peak head accelerations, trunk contacts, and offensive performance were quantified during the SC trials using accelerometery and video analysis. RPE was assessed in both the SP and SC trials. Results: RPE was significantly greater in the caffeine (11.3 [2.0]) than placebo (9.9 [1.9]) condition postpractice (P = .002), with a trend toward greater RPE in caffeine (16.9 [1.8]) than placebo (15.7 [2.8]) post-SC (P = .05). There was a greater number of peak head accelerations in the caffeine (4.35 [0.24]) than placebo (4.14 [0.24]) condition (P = .028). Performance times, error rate, and RPE were not different between intervention conditions during the SP trials (P > .05). Conclusions: A low dose of caffeine has limited impact on sport-specific skill performance and RPE but may enhance physicality during ice hockey SCs.
Simona Bar-Haim, Ronit Aviram, Anat Shkedy Rabani, Akram Amro, Ibtisam Nammourah, Muhammed Al-Jarrah, Yoav Raanan, Jack A. Loeppky and Netta Harries
Purpose: Exercise interventions have been shown to increase motor capacities in adolescents with cerebral palsy; however, how they affect habitual physical activity (HPA) and sedentary behavior is unclear. The main objective was to correlate changes in HPA with changes in mobility capacity following exercise interventions. Methods: A total of 54 participants (aged 12–20 y) with bilateral spastic cerebral palsy at Gross Motor Function Classification System (GMFCS) levels II and III received 4 months of group progressive resistance training or treadmill training. Mobility measurements and HPA (averaged over 96 h) were made before and after interventions. Results: Averaged baseline mobility and HPA measures and improvements in each after both interventions were positively correlated in all participants. Percentage of sedentary/awake time decreased 2%, with significant increases in HPA measures of step count (16%), walk time (14%), and upright time (9%). Mobility measures and HPA changes were quite similar between Gross Motor Function Classification System levels, but improvement in HPA after group progressive resistance training was greater than after treadmill training (12% vs 4%) and correlated with mobility improvement. Conclusions: Mobility capacity improved after these interventions and was clearly associated with improved HPA. The group progressive resistance training intervention seems preferable to improve HPA, perhaps related to greater social interaction and motivation provided by group training.
Llion A. Roberts, Johnpaul Caia, Lachlan P. James, Tannath J. Scott and Vincent G. Kelly
Purpose: External counterpulsation (ECP) has previously been used to treat cardiac patients via compression of the lower extremities during diastole to increase venous return and coronary perfusion. However, the effects of ECP on exercise performance and markers of recovery in elite athletes are largely unknown. Methods: On 2 separate occasions, 48 h apart, 7 elite National Rugby League players performed an identical 60-min field-based conditioning session followed by a 30-min period of either regular ECP treatment or placebo. Power measures during repeated cycle bouts and countermovement jump height and contraction time derivatives were measured at rest and 5 h postexercise. Saliva samples and venous blood samples were taken at rest, postexercise, and 5 h postexercise to assess stress, inflammation, and muscle damage. Results: After ECP treatment, cycling peak power output (P = .028; 11%) and accumulated peak power (P = .027; 14%) increased compared with the placebo condition. Postexercise plasma interleukin 1 receptor antagonist only increased after ECP (P = .024; 84%), and concentrations of plasma interleukin 1 receptor antagonist tended to be higher (P = .093; 76%) 5 h postexercise. Furthermore, testosterone-to-cortisol ratio was increased above baseline and placebo 5 h postexercise (P = .017–.029; 24–77%). The ratio of postexercise salivary α-amylase to immunoglobulin A decreased after treatment (P = .013; 50%) compared with the placebo control. Conclusions: Exercise performance and hormonal indicators of stress were improved and inflammation markers were reduced following acute ECP.