Aberrant loading is a mechanism by which individuals with chronic ankle instability (CAI) may negatively impact cartilage health and therefore long-term health outcomes. We aimed to quantify walking vertical ground reaction force (vGRF) component differences between those with and without CAI. Participants (n = 36) walked barefoot overground at a self-selected comfortable pace. Normalized peak vGRF, time to peak vGRF, and normalized loading rate were calculated. Higher normalized loading rates (CAI: 5.69 ± 0.62 N/BW/s; controls: 5.30 ± 0.44 N/BW/s, p = .034) and less time to peak vGRF (CAI: 1.48 ± 0.18 s; controls: 1.62 ± 0.16 s, p = .018) were observed in those with CAI. In conclusion, those with CAI demonstrate a higher normalized loading rate and less time to peak vGRF compared to controls.
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Erik A. Wikstrom, Kyeongtak Song, Kimmery Migel and Chris J. Hass
Chi-Whan Choi, Jung-Wan Koo and Yeon-Gyu Jeong
Context: The modified side-bridge exercise is designed for some special situations in which it is impossible to tolerate the compressive load on the side supported during the side bridge, such as in the older people with a hip or knee replacement and even in athletes with shoulder pain. Objectives: To examine the effects of 3 modified side-bridge exercises on the spinal stability muscles compared with traditional side-bridge (TSB) exercises for healthy men. Design: The effects of different exercises on the muscle activities of the external oblique (EO), internal oblique (IO), and quadratus lumborum (QL) during TSB exercise, both legs lift on side lying (BLLS), torso lift on a 45° bench while side lying (TLBS), and wall side bridge (WSB) were analyzed with the 1-way repeated-measures analysis of variance. Setting: This study was conducted in a university hospital laboratory. Participants: A total of 20 healthy men were recruited for this study. Interventions: The participants performed TSB, BLLS, TLBS, and WSB in a random order. Main Outcome Measures: Surface electromyography measured the muscle activity of the EO, IO, and QL. A 1-way repeated-measures analysis of variance assessed the statistical significance of the EO, IO, and QL muscle activity. When there was a significant difference, a Bonferroni adjustment was performed. Results: BLLS and TLBS showed similar effects to TSB in the EO, IO, and QL muscle activity, whereas WSB showed significantly less QL muscle activity than TSB (P < .05). Moreover, TLBS was significantly greater in the muscle activity of QL and EO than WSB (P < .05). Conclusion: BLLS and TLBS may be effective rehabilitation techniques to activate EO, IO, and QL in patients who are unable to perform TSB as spine stability exercises.
Ryan Thomson, Danielle Carabello, Jamie Mansell and Anne Russ
Clinical Question: In retired National Football League (NFL) players, what is the prevalence of depression after sustaining concussions? Clinical Bottom Line: There is emerging evidence to support the clinical question that retired NFL players with a history of concussion may be diagnosed with depression.
Kim Gammage, Rachel Arnold, Lori Dithurbide, Alison Ede, Karl Erickson, Blair Evans, Larkin Lamarche, Sean Locke, Eric Martin and Kathleen Wilson
Context: Joint position sense (JPS) tests of proprioception lack ecological validity because the testing conditions are so different from the normal function that they can contribute little to understanding the role proprioception plays in daily and sporting activities. Objective: To evaluate the effect of low and high external load on the knee JPS and to investigate the relationship between maximum voluntary isometric contraction and force sense (FS). Design: Experimental study. Setting: Research laboratory. Participants: A total of 47 volunteers with no history of knee pathology. Interventions: Three active JPS tests performed with no load, low load, and high load were compared at the 45° target angle. For isometric FS test, 50% load was used. For isotonic low load and high load JPS tests, 30% and 70% loads were applied, respectively. Main Outcome Measures: To analyze obtained data set 2-way multiple analysis of variance, repeated measures of analysis of variance, paired sample t test, and the Pearson correlation coefficient were used. Results: JPS was not affected by gender (male and female) and activity levels (sedentary, recreational, and trained). Results of the repeated measure of analysis of variance demonstrated the significant main effect of loads (P = .001). Significant differences were found between no load, low load, and high load JPS (P = .001). A positive and significant correlation was found between maximum voluntary isometric contraction and FS error values (r = .41, P = .001). Conclusions: The results suggest that as the load level increases, the knee JPS improves. Knee JPS assessed under external load may be a more appropriate alternative to the nature of the sport. Those with higher muscle strength have a worse FS.
Emma L. Sweeney, Daniel J. Peart, Irene Kyza, Thomas Harkes, Jason G. Ellis and Ian H. Walshe
Experimental sleep restriction (SR) has demonstrated reduced insulin sensitivity in healthy individuals. Exercise is well-known to be beneficial for metabolic health. A single bout of exercise has the capacity to increase insulin sensitivity for up to 2 days. Therefore, the current study aimed to determine if sprint interval exercise could attenuate the impairment in insulin sensitivity after one night of SR in healthy males. Nineteen males were recruited for this randomized crossover study which consisted of four conditions—control, SR, control plus exercise, and sleep restriction plus exercise. Time in bed was 8 hr (2300–0700) in the control conditions and 4 hr (0300–0700) in the SR conditions. Conditions were separated by a 1-week entraining period. Participants slept at home, and compliance was assessed using wrist actigraphy. Following the night of experimental sleep, participants either conducted sprint interval exercise or rested for the equivalent duration. An oral glucose tolerance test was then conducted. Blood samples were obtained at regular intervals for measurement of glucose and insulin. Insulin concentrations were higher in SR than control (p = .022). Late-phase insulin area under the curve was significantly lower in sleep restriction plus exercise than SR (862 ± 589 and 1,267 ± 558; p = .004). Glucose area under the curve was not different between conditions (p = .207). These findings suggest that exercise improves the late postprandial response following a single night of SR.
Alexandra F. DeJong and Jay Hertel
Treadmill running analyses cannot adequately replicate outdoor running demands, and wearable sensors offer a means to overcome this clinical limitation. The purpose of this report is to describe five individual runners’ biomechanical outcomes during hill and track intervals, stroller running, and 5- and 21-K races using wearable sensors. Step rates and lengths increased while foot contact time decreased during sprints and 5-K race portions. Stroller running increased step rate, length, and pronation. Step length decreased and pronation and foot contact time increased over the 21-K race. Wearable sensors helped identify patterns in natural training environments as a basis for clinical application.
Kami N. Thews, Zachary K. Winkelmann, Lindsey E. Eberman, Kirsten A. Potts and Kenneth E. Games
Firefighters are exposed to psychological stress while on duty that could lead to mental and behavioral illnesses that may go unreported. We surveyed firefighters to identify their perceived barriers encountered when attempting to report a mental and behavioral illness with a follow-up question related to how difficult the selected barrier was in the reporting process. A total of 314 firefighters completed the instrument, with most indicating they experienced cultural barriers such as social norms from administration and peers. The findings demonstrate an overall demand for a cultural change within the fire service for a supportive environment that encourages reporting.
Jeffrey G. Williams, Lauryn Darnall and Conrad Schumann
Baseball players have demonstrated greater thoracolumbar rotation (TLR) range of motion (ROM) toward their nonthrowing arm sides. This imbalance is thought to be compensatory to ROM deficiencies at the throwing arm’s shoulder. The purpose of this study was to examine the relationship between TLR and glenohumeral (GH) ROM measures (internal rotation, external rotation, horizontal adduction) among collegiate baseball players. Findings demonstrated limited and no relationships between TLR and GH ROM. Future research should advance these findings by examining symptomatic participants and hip ROM as additional variables. Doing so may enhance clinicians’ abilities to comprehensively predict, prevent, detect, and treat movement deficiencies, and subsequent injuries, suffered by competitive baseball players.
Joowon Lee, Baojiang Chen, Harold W. Kohl III, Carolyn E. Barlow, Chong Do Lee, Nina B. Radford, Laura F. DeFina and Kelley P. Gabriel
The purpose of the current investigation was to examine the cross-sectional associations of participation in muscle-strengthening activities (MSAs) with carotid intima–media thickness (CIMT) among older adults. The data are from 2,557 older adult participants enrolled in an observational cohort who reported no history of cardiovascular disease. MSA was determined using a questionnaire. Carotid ultrasound was performed to measure the CIMT of the common carotid artery bilaterally. Logistic regression models were constructed to estimate the association of MSA with CIMT after adjustment for potential confounders. The participants were aged 68.6 ± 7.0 years, and the majority were male (71.7%) and White (96.5%); 18% had abnormal CIMT. Meeting the physical activity guidelines for MSA was inversely associated with abnormal CIMT after adjustment for age and sex. However, this observed inverse relation became statistically null after further adjustment for cardiovascular disease risk factors, including aerobic physical activity.