The electromyographic (EMG) normalization (often to maximum voluntary isometric contraction [MVIC]) is used to control for interparticipant and day-to-day variations. Repeated MVIC exertions may be inadvisable from participants’ safety perspective. This study developed a technique to predict the MVIC EMG from submaximal isometric voluntary contraction EMG. On day 1, 10 participants executed moment exertions of 100%, 60%, 40%, and 20% of the maximum (biceps brachii, rectus femoris, neck flexors, and neck extensors) as the EMG data were collected. On day 2, the participants replicated the joint moment values from day 1 (60%, 40%, and 20%) and also performed MVIC exertions. Using the ratios between the MVIC EMGs and submaximal isometric voluntary contraction EMG data values established on day 1, and the day 2 submaximal isometric voluntary contraction EMG data values, the day 2 MVIC EMGs were predicted. The average absolute percentage error between the predicted and actual MVIC EMG values for day 2 were calculated: biceps brachii, 45%; rectus femoris, 27%; right and left neck flexors, 27% and 33%, respectively; and right and left neck extensors, both 29%. There will be a trade-off between the required accuracy of the MVIC EMG and the risk of injury due to exerting actual MVIC. Thus, using the developed predictive technique may depend on the study circumstances.
Hamid Norasi, Jordyn Koenig, and Gary A. Mirka
Yan-Xia Li, Lin Li, Zhi-Qiang Cai, Xu-Xue Zhou, Xiu-Jun Hao, and Li Li
This study aimed to explore the effect of sex and force level on grip force reproduction in healthy adults by conducting a force reproduction task. Participants (n = 28) were instructed to replicate a range of reference grip force levels (10–130 N in 10 N increments). We found that women (absolute error: 16.2 ± 8.7 N) replicated these force levels more accurately than men (absolute error: 23.1 ± 9.5 N) at higher force levels (90–130 N). Furthermore, the force reproductions were most accurate at the 30–50 N range for men and the 50–60 N range for women. These results may offer significant insights into the higher rates of musculoskeletal disorders among women, enabling researchers and clinicians to design novel interventions and tools that can improve grip force perception and reduce hand injury rates in both men and women.
Misia Gervis, Helen Pickford, Hanna Nygârd, and Aura Goldman
Injuries, and their psychological and maladaptive behavioral consequences, are an inevitable by-product of sport participation. This study sought to investigate the prevalence of maladaptive behaviors and psychological corollaries of long-term injury in order to understand if these are universal experiences of long-term injured athletes. Competitive athletes (n = 187; average time spent injured =43 weeks), across a range of sports completed an online questionnaire developed to investigate the psychological and behavioral consequences of long-term injury. Results indicated that negative symptoms after injury were a universal experience and are the “normal” response to injury, not the “exception.” The most prevalent psychological consequences were rumination (97.9%), boredom (94.7%), and fear of reinjury (93.6%). Furthermore, indicators of suicidal ideation were reported by more than 50% of participants. Factor analysis revealed a six-factor model: (a) self-sabotaging behavior, (b) daily functioning, (c) addictive behavior, (d) clinical issues, (e) fixation on injury, and (f) compromised athletic identity. All factors significantly correlated with debilitating impact. Thus, this study calls for a change to the support of long-term injured athletes to include routine psychological care.
Lindsey E. Slavin, Tess M. Palmateer, Trent A. Petrie, and E. Whitney G. Moore
The onset of COVID-19 and cancellation of collegiate sports may have exacerbated student-athletes’ psychological distress. Within a national sample of collegiate athletes (N = 5,755; 66.7% women), we determined how gender and race related to rates of depression, stress, and counseling use at the beginning of the pandemic (April/May 2020). Overall, 26.5% (n = 1,526) and 10.6% (n = 612) endorsed clinical levels of depression and stress, respectively; 25.1% (n = 1,443) and 69.7% (n = 4,014) reported subclinical levels. Few athletes (2.3%–17.1%) reported counseling use before or after the onset of COVID-19; those who did reported higher levels of depression and stress than those who never sought services. The female athletes reported higher rates of depression, stress, and counseling use than the male athletes. There were no race effects. Athletic departments must address their student-athletes’ psychological distress by facilitating a higher use of mental health services.
Shohei Shibata, Yuki Inaba, Shinsuke Yoshioka, and Senshi Fukashiro
The purpose of this study is to examine changes in the kinetic parameters of the fingers caused by differences in ball velocity during overarm throwing. Six baseball players participated in the study, and the kinetics of the wrist and metacarpophalangeal (MP) joint were calculated using an inverse dynamics method. The results of Tukey’s multiple comparison tests showed that the torque and work of the wrist increased with increasing ball velocity (p < .05), indicating that wrist torque and work contributed to the adjustment of ball velocity. Peak MP joint torque also increased with ball velocity (p < .05), although the work of the MP joint remained relatively constant. We conclude that MP joint torque and work contribute to the achievement of stable ball release rather than adjusting ball velocity.
Lewis King, SarahJane Cullen, Jean McArdle, Adrian McGoldrick, Jennifer Pugh, Giles Warrington, and Ciara Losty
A large proportion of jockeys report symptoms associated with mental health difficulties (MHDs), yet most do not seek help from professional mental health support services. Due to the paucity of literature in this field, this study sought to explore jockeys’ barriers to, and facilitators of, help-seeking for MHDs. Twelve jockeys participated in semistructured interviews, subsequently analyzed via reflexive thematic analysis. Barriers to help-seeking included the negative perceptions of others (stigma and career implications), cultural norms (masculinity and self-reliance), and low mental health literacy (not knowing where to seek help, minimization of MHDs, negative perceptions of treatment, and recognizing symptoms). Facilitators to help-seeking included education (exposure to psychological support at a younger age), social support (from professionals, jockeys, family, and friends), and media campaigns (high-profile disclosures from jockeys). Findings are consistent with barrier and facilitator studies among general and athletic populations. Applied recommendations and future research considerations are presented throughout the manuscript.
Fitness centers may be an ideal setting for physical activity, yet qualitative findings suggest social-level barriers constrain access for people with disabilities. To further test this, I employed an online message correspondence study to investigate the effect of impairment status on the responsiveness of a national sample of fitness centers to requests for services. Email requests were sent to 800 fitness centers, of which 200 were tailored to each of the four investigative conditions (i.e., control, vision loss, spinal cord injury, or being autistic). The odds of receiving a positive response were 40.5% lower for individuals with vision loss (p = .011) and 33.3% lower for individuals with spinal cord injury (p = .055), as compared with individuals without an impairment. Specifically, the odds of receiving a positive response for personal training were 58.8% lower among individuals with vision loss (p = .003) and 41.1% lower for individuals with spinal cord injury (p = .065).
Joshua Thomas, Thomas Murphy, Steve Tran, Samuel J. Howarth, David Starmer, and Martha Funabashi
Investigating all forces exerted on the patient’s body during high-velocity, low-amplitude spinal manipulative therapy (SMT) remains fundamental to elucidate how these may contribute to SMT’s effects. Previous conflicting findings preclude our understanding of the relationship between SMT forces acting at the clinician–patient and patient–table interfaces. This study aimed to quantify forces at the clinician–participant and participant–table interfaces during thoracic SMT in asymptnomatic adults. An experienced clinician provided a posterior to anterior SMT centered to T7 transverse processes using predetermined force–time characteristics to 40 asymptomatic volunteers (20 females; average age = 27.2 [4.9] y). Forces at the clinician–participant interface were recorded by triaxial load cells; whereas, forces at the participant–table interface were recorded by the force-sensing table technology. Preload force, total peak force, time to peak, and loading rate at each interface were analyzed descriptively. Total peak vertical forces at the clinician–participant interface averaged 532 (71) N while total peak forces at the participant–table interface averaged 658 (33) N. Forces at the participant–table interface were, on average, 1.27 (0.25) times larger than the ones at the clinician–participant interface. Larger forces at the participant–table interface compared with the ones at the clinician–participant interface during thoracic SMT are consistent with mathematical models developed to investigate thoracic impact simulating a dynamic force-deflection response.