Sixteen men completed four trials at random as follows: (Trial A) performance of a single bout of resistance exercise preceded by placebo ingestion (vitamin C); (Trial B) ingestion of 1,500 mg L-arginine and 1,500 mg L-lysine, immediately followed by exercise as in Trial A; (Trial C) ingestion of amino acids as in Trial B and no exercise; (Trial D) placebo ingestion and no exercise. Growth hormone (GH) concentrations were higher at 30,60, and 90 min during the exercise trials (A and B) compared with the resting trials (C and D) (p < .05). No differences were noted in [GH] between the exercise trials. [GH] was significantly elevated during resting conditions 60 min after amino acid ingestion compared with the placebo trial. It was concluded that ingestion of 1,500 mg arginine and 1,500 mg ly sine immediately before resistance exercise does not alter exercise-induced changes in [GH] in young men. However, when the same amino acid mixture is ingested under basal conditions, the acute secretion of GH is increased.
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Richard R. Suminski, Robert J. Robertson, Fredric L. Goss, Silva Arslanian, Jie Kang, Sergio DaSilva, Alan C. Utter and Kenneth F. Metz
Ben D. Kern, Kim C. Graber, Amelia Mays Woods and Tom Templin
Physical education teachers have been criticized for not implementing progressive or innovative instruction resulting in enhanced student knowledge and skills for lifetime participation in physical activity. Purpose: To investigate how teachers with varying dispositions toward change perceive socializing agents and teaching context as barriers to or facilitators of making pedagogical change. Methods: Thirty-two teachers completed a survey of personal dispositions toward change and participated in in-depth interviews. Results: Teachers perceived that students’ response to instructional methods and student contact time (days/week), as well as interactions with teaching colleagues and administrators influenced their ability to make pedagogical changes. Teachers with limited student contact time reported scheduling as a barrier to change, whereas daily student contact was a facilitator. Change-disposed teachers were more likely to promote student learning and assume leadership roles. Conclusion: Reform efforts should include consideration of teacher dispositions and student contact time.
Artur Direito, Joseph J. Murphy, Matthew Mclaughlin, Jacqueline Mair, Kelly Mackenzie, Masamitsu Kamada, Rachel Sutherland, Shannon Montgomery, Trevor Shilton and on behalf of the ISPAH Early Career Network
Increasing population levels of physical activity (PA) can assist in achieving the United Nations sustainable development goals, benefiting multiple sectors and contributing to global prosperity. Practices and policies to increase PA levels exist at the subnational, national, and international levels. In 2018, the World Health Organization launched the first Global Action Plan on Physical Activity (GAPPA). The GAPPA provides guidance through a framework of effective and feasible policy actions for increasing PA, and requires engagement and advocacy from a wide spectrum of stakeholders for successful implementation of the proposed actions. Early career professionals, including researchers, practitioners, and policymakers, can play a major role with helping “all people being regularly active” by contributing to 4 overarching areas: (1) generation—of evidence, (2) dissemination—of key messages and evidence, (3) implementation—of the evidence-based actions proposed in the GAPPA, and (4) contributing to advocacy for robust national action plans on PA. The contribution of early career professionals can be achieved through 5 pathways: (1) research, (2) workplace/practice, (3) business, (4) policy, and (5) professional and public opinion. Recommendations of how early career professionals can contribute to the generation, dissemination, and implementation of the evidence and actions proposed by the GAPPA are provided.
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  y; height: 178  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.
Joseph B. Lesnak, Dillon T. Anderson, Brooke E. Farmer, Dimitrios Katsavelis and Terry L. Grindstaff
Context: Resistance training exercise prescription is often based on exercises performed at a percentage of a 1-repetition maximum (1RM). Following knee injury, there is no consensus when a patient can safely perform 1RM testing. Resistance training programs require the use of higher loads, and loads used in knee injury rehabilitation may be too low to elicit gains in strength and power. A maximum isometric contraction can safely be performed during early stages of knee rehabilitation and has potential to predict an isotonic knee extension 1RM. Objective: To determine whether a 1RM on an isotonic knee extension machine can be predicted from isometric peak torque measurements. Design: Descriptive laboratory study. Setting: University research laboratory. Participants: A total of 20 (12 males and 8 females) healthy, physically active adults. Main Outcome Measures: An isokinetic dynamometer was used to determine isometric peak torque (in N·m). 1RM testing was performed on a knee extension machine. Linear regression was used to develop a prediction equation, and Bland–Altman plots with limits of agreement calculations were used to validate the equation. Results: There was a significant correlation (P < .001, r = .926) between peak torque (283.0 [22.6] N·m) and the knee extension 1RM (69.1 [22.6] kg). The prediction equation overestimated the loads (2.3 [9.1] kg; 95% confidence interval, −15.6 to 20.1 kg). Conclusions: The results show that isometric peak torque values obtained on an isokinetic dynamometer can be used to estimate 1RM values for isotonic knee extension. Although the prediction equation tends to overestimate loads, the relatively wide confidence intervals indicate that results should be viewed with caution.
Aisha Chen, Sandhya Selvaraj, Vennila Krishnan and Shadnaz Asgari
Accurate and reliable detection of the onset of gait initiation is essential for the correct assessment of gait. Thus, this study was aimed at evaluation of the reliability and accuracy of 3 different center of pressure–based gait onset detection algorithms: A displacement baseline–based algorithm (method 1), a velocity baseline–based algorithm (method 2), and a velocity extrema–based algorithm (method 3). The center of pressure signal was obtained during 10 gait initiation trials from 16 healthy participants and 3 participants with Parkinson’s disease. Intrasession and absolute reliability of each algorithm was assessed using the intraclass correlation coefficient and the coefficient of variation of center of pressure displacement during the postural phase of gait initiation. The accuracy was evaluated using the time error of the detected onset by each algorithm relative to that of visual inspection. The authors’ results revealed that although all 3 algorithms had high to very high intrasession reliabilities in both healthy subjects and subjects with Parkinson’s disease, methods 2 and 3 showed significantly better absolute reliability than method 1 in healthy controls (P = .001). Furthermore, method 2 outperformed the other 2 algorithms in both healthy subjects and subjects with Parkinson’s disease with an overall accuracy of 0.80. Based on these results, the authors recommend using method 2 for accurate and reliable gait onset detection.
Javad Sarvestan and Zdeněk Svoboda
Background: Taping is a preventive measure commonly used for protecting and strengthening the ankle joint to prevent further musculoskeletal damage. Ankle taping prevents excessive range of motion (ROM) of the ankle joint and allows the improvement of proprioception to adjust balance. Appropriate ankle stability is essential for various activities, such as sprinting, turning, cutting, and jumping, which are associated with agility. Aim: To assess the acute effect of Kinesio taping and athletic taping on the ankle ROM of athletes with chronic ankle sprain during various agility tests that include sprinting, turning, and cutting actions. Methods: Twenty-five physically active volunteers with chronic ankle sprain performed the Illinois, 5–0–5, 10-m shuttle, hexagon, compass drill, and T agility tests in 3 ankle conditions (nontaped, Kinesio taped, and athletic taped), in random order. Ankle ROM was recorded using the Vicon motion capture system. Results: In comparison with the nontaped ankle condition, in the ankle Kinesio-taping condition, the results showed a significant increase of ankle ROM in the sprinting part of the Illinois, 5–0–5, 10-m shuttle, and T agility tests (P ≤ .01), whereas in the ankle athletic-taping condition, no significant difference was found in ankle ROM during all agility tests. Conclusion: In sports that need linear sprinting, Kinesio taping seems to be a suitable intervention for the improvement of sports performance as it provides increased ankle ROM.
Kimberly Somers, Dustin Aune, Anthony Horten, James Kim and Julia Rogers
Context: Limited ankle dorsiflexion (DF) range of motion has been correlated with decreased flexibility of the gastrocnemius/soleus complex. Decreased ankle DF range of motion can lead to an increase in lower-extremity injuries, for example, acute ankle sprains, Achilles tendinopathy. Objective: The purpose of this study was to determine whether a single application of the intervention to the gastrocnemius/soleus complex via multidirectional self-myofascial release using a foam roller, multiplanar dynamic stretch performed in downward dog, or a combination of both techniques acutely improved ankle DF. Design: Subjects were assigned to groups via random card selection. Investigators provided verbal cues as needed to yield correct performance of interventions. Both interventions were performed twice for 1 minute using a dynamic walking rest of 30.48 m at a self-selected pace between interventions. Statistical analyses were completed using a 1-way analysis of variance, at α level ≤ .05. Setting: A convenience sample study. Participants: A total of 42 asymptomatic physical therapy students (18 females and 24 males) with mean age of 26.12 (4.03) years volunteered to participate. Interventions: Multidirectional self-myofascial release using a foam roller, multiplanar dynamic stretch performed in downward dog, or a combination of both techniques. Main Outcome Measures: Weight-bearing right ankle DF measurements were recorded in centimeters using a forward lunge technique (intraclass correlation coefficient = .98, .97, and .96). Results: Data analysis revealed no significant difference between the 3 groups in all pre–post measurements (P = .82). Mean (SD) measurements from pretest to posttest for myofascial release, dynamic stretching, and combination interventions were 0.479 (0.7) cm, 0.700 (0.7) cm, and 0.907 (1.4) cm, respectively. Conclusion: Until further studies are conducted, the selection of technique to increase ankle DF range of motion should be based on each individual patient’s ability, preference, and response to treatment.
Guilherme S. Nunes, Débora Faria Wolf, Daniel Augusto dos Santos, Marcos de Noronha and Fábio Viadanna Serrão
Context: People with patellofemoral pain (PFP) present altered lower-limb movements during some activities. Perhaps, joint misalignment in the hip is one of the reasons for altered movement patterns in people with PFP. Some mobilization techniques have been designed to address joint misalignments. Objective: To investigate the acute effects of hip mobilization with movement (MWM) technique on pain and biomechanics during squats and jumps in females with and without PFP. Design: Randomized, placebo-controlled trial. Setting: Movement analysis laboratory. Patients: Fifty-six physically active females (28 with PFP and 28 asymptomatic) were divided into 4 groups: experimental group with PFP, sham group with PFP, experimental group without PFP, and sham group without PFP. Intervention(s): The experimental groups received MWM for the hip, and the sham groups received sham mobilization. Main Outcome Measures: Pain, trunk, and lower-limb kinematics, and hip and knee kinetics during single-leg squats and landings. Results: After the interventions, no difference between groups was found for pain. The PFP experimental group decreased hip internal rotation during squats compared with the PFP sham group (P = .03). There was no other significant difference between PFP groups for kinematic or kinetic outcomes during squats, as well as for any outcome during landings. There was no difference between asymptomatic groups for any of the outcomes in any of the tasks. Conclusions: Hip mobilization was ineffective to reduce pain in people with PFP. Hip MWM may contribute to dynamic lower-limb realignment in females with PFP by decreasing hip internal rotation during squats. Therefore, hip MWM could be potentially useful as a complementary intervention for patients with PFP.