The purpose of this research was to evaluate the algorithm DeepLabCut (DLC) against a 3D motion capture system (Vicon Motion Systems Ltd) in the analysis of lumbar and elbow flexion–extension movements. Data were acquired concurrently and tracked using DLC and Vicon. A novel DLC model was trained using video data derived from a subset of participants (training group). Accuracy and precision were assessed using data derived from the training group as well as in a new set of participants (testing group). Two-way analysis of variance were used to detect significant differences between the training and testing sets, capture methods (Vicon vs DLC), as well as potential higher order interaction effect between these independent variables in the estimation of flexion–extension angles and variability. No significant differences were observed in any planar angles, nor were any higher order interactions observed between each motion capture modality with the training versus testing data sets. Bland–Altman plots were used to depict the mean bias and level of agreement between DLC and Vicon for both training and testing data sets. This research suggests that DLC-derived planar kinematics of both the elbow and lumbar spine are of acceptable accuracy and precision when compared with conventional laboratory gold standards (Vicon).
Paul N. Goncharow and Shawn M. Beaudette
Michael VanNostrand, Brittany Belanger, Gabriel Purin, Susan L. Kasser, and Michael Cannizzaro
The present study expands on current understanding of dual-task cognitive-motor interference, by including cortical activation measures to both traditional and ecologically valid dual-task paradigms. Fifteen individuals with multiple sclerosis and 14 control participants underwent mobility testing while wearing functional near-infrared spectroscopy. In the absence of increased prefrontal cortical activation, subjects with multiple sclerosis performed significantly worse on measures of cognition under both single- and dual-task conditions. These findings suggest that persons with multiple sclerosis may be unable to allocate additional cortical resources to cognition under dual-task conditions, leading to significant cognitive-motor interference and decrements in performance. This study is the first to investigate cortical activation across several commonly used and ecologically valid dual-task assessments.
Heather M. Hamilton and Rumit Singh Kakar
Sex-based analyses are important when studying running kinematics. Females experience a unique aging process and demonstrate differences in running biomechanics from males. The purpose was to determine the relationship between age and running kinematics in female runners. Forty-six female runners (18–65 y) ran at self-selected jogging and maximal speed on a treadmill. Lower-extremity joint kinematics were calculated, and 2 principal component analyses (jogging speed and maximal speed) were performed from kinematic variables. Regression was used to examine the relationship between age and identified components, and between age and the variables with the highest loadings within these components. For jogging speed, there was a positive relationship between age and ankle varus at initial contact and a negative relationship between age and peak eversion, hip adduction, knee flexion, dorsiflexion, and hip adduction at initial contact (Ps < .05). For maximal speed, initial contact ankle frontal plane angle became more positive with age, and there was a negative relationship with age and peak eversion, dorsiflexion and knee flexion, and knee flexion and hip adduction at initial contact (Ps < .05). Primarily distal joint angles decreased with increasing age in female recreational runners at self-selected running speeds.
Jean-Francois Esculier, Jesse M. Charlton, Natasha M. Krowchuk, Julia De Pieri, and Michael A. Hunt
The objective of this study was to compare the immediate effects of modifications to footwear or cadence on lower limb biomechanics of female Masters runners. After analyzing habitual treadmill running biomechanics in 20 female runners (52.4 [8.3] y), we assessed the effects of 5 conditions: (1) barefoot running, (2) Merrell Vapor Glove, (3) Merrell Bare Access, (4) Brooks Pure Flow, and (5) increasing cadence by 10%. In comparison with habitual biomechanics, greater vertical loading rates of the ground reaction force were observed during running barefoot or with a Merrell Vapor Glove or Bare Access. There was high variability among participants as to changes in foot kinematics during the conditions. Running barefoot (−26.0%) and with a Merrell Vapor Glove (−12.5%) reduced sagittal plane knee moments, but increased sagittal plane ankle moments (both 6.1%). Increasing cadence by 10% resulted in a more modest decrease in knee flexion moments (−7.7%) without increasing peak external ankle dorsiflexion moments. When asked if they would prefer minimalist shoes or increasing cadence, 11 participants (55%) chose cadence and 9 (45%) chose footwear. Minimalist footwear decreased sagittal knee moments, but increased vertical loading rate and sagittal ankle moments. Increasing cadence may be useful to lower sagittal knee moments without increasing ankle moments.
Karen A. Smith, Robert J. Naughton, Carl Langan-Evans, and Kiara Lewis
This mixed methods study aimed to investigate weight cutting practices of female taekwon-do athletes internationally and explore their experiences of “making weight.” A survey of weight loss practices and eating behaviors was completed by 103 taekwon-do athletes from 12 countries, which illustrated that 72.5% of athletes engage in both acute and chronic weight loss practices prior to competition and that there were higher levels of disordered eating within this athletic population than nonweight cutting athletes. Semistructured interviews were conducted with five international-level competitors; thematic analysis of the interviews identified that the women in general felt weight cutting was “horrible—but worth it” and the women believed that (a) weight cutting is unpleasant, difficult, and challenging; and (b) weight cutting provides a competitive advantage. The implications of this study are that weight cutting is widespread among high-level competitive female taekwon-do athletes and this is unlikely to change given the perceived advantages. Efforts are needed to make sure that the women are knowledgeable of the risks and are provided with safe and effective means of making weight.
Satu Kaski, Monna Arvinen-Barrow, Ulla Kinnunen, and Jari Parkkari
The aim of the present study was to identify profiles of elite athlete mental well- and ill-being and study how the profiles (i.e., subgroups of athletes) differed in sport-related demands and resources. A total of 259 Finnish elite athletes (n = 170 active and n = 89 retired) completed quantitative self-report inventories. Through cluster analysis, four profiles of mental well- and ill-being were identified. Profile 1 was overrepresented by retired, older, and male athletes, and characterized by good mental well-being. Profile 2 consisted mainly of active athletes who reported mild risk for alcohol abuse. Profile 3 consisted mainly of women who displayed possible presence of an eating disorder. Profile 4 was typical of young athletes with mental ill-being. The balance between sport-related demands and resources appeared to be the healthiest in Profile 1 and worst in Profile 4. The present findings are beneficial for those who work with and/or provide psychological support to athletes.
Courtney C. Walton, Kelsey J. Lewis, James Kirby, Rosemary Purcell, Simon M. Rice, and Margaret S. Osborne
This cross-sectional study explored athlete responses to the Compassion Motivation and Action Scales Self-Compassion Scale, examining its relationship with well-being. Athlete (N = 207; mean age 27.9 years) scores were consistent with previous population means. Scores on the Compassion Motivation and Action Scales Self-Compassion Scale did not differ between elite and nonelite athletes, nor did they correlate significantly with trait competitiveness. Significant differences emerged based on athlete well-being state, with athletes categorized as “flourishing” scoring higher on the total score and all subscales of the Compassion Motivation and Action Scales Self-Compassion Scale, as compared with those with “moderate mental health” (Cohen’s ds from 0.58 to 0.92). Furthermore, the distress tolerance subscale significantly mediated the relationship between self-compassion intentions and well-being (indirect path: B = 0.034, p < .001). The results suggest that self-compassionate intentions are not enough, and athletes may need support to tolerate the distress that comes with moving toward one’s own suffering.
Ana Rubio-Morales, Jesús Díaz-García, Carlos Barbosa, Jelle Habay, Miguel Ángel López-Gajardo, and Tomás García-Calvo
Experts have highlighted the importance of coaches knowing the level of mental fatigue (MF) induced by different tasks. This study aimed to compare the mentally fatiguing nature of cognitive, physical, and combined tasks and, additionally, assess the effect of different moderating variables on MF. Twenty-three physically active (16 males: M age = 24 years; seven females: M age = 22.57 years) participants performed three experimental sessions: (a) physically fatiguing: 30 min of cycloergometer work (at 65%–75% of maximum heart rate), (b) mentally fatiguing: 30 min of an incongruent Stroop task, and (c) mixed fatiguing: 30 min of combining the physically and mentally fatiguing protocols. Subjective MF (visual analog scale), reaction time (psychomotor vigilance task), and cognitive performance (Stroop) were measured throughout the different protocols. Results showed significant increments in subjective MF after all tasks, with the mental and mixed protocols showing significantly higher increases. Only the mentally fatiguing protocol caused significant impairments in reaction time. No significant effects of sex, years of experience, or degree of mental toughness were observed. These results suggest that the use of all these tasks, and especially the mentally fatiguing exercises, should be avoided immediately prior to competitions due to the negative consequences of MF on performance. Moreover, this effect seems to be independent of the sex, years of experience, or mental toughness of athletes.
Cong Peng, Na Yao, Xin Wang, and Dangxiao Wang
This study examined whether within-a-hand and between-hands finger pairings would exhibit different interfinger synchronization capabilities in discrete fine-force control tasks. Participants were required to perform the designed force control tasks using finger pairings of index and middle fingers on one or two hands. Results demonstrated that the delayed reaction time and the timing difference of paired fingers showed a significant difference among finger pairings. In particular, paired fingers exhibited less delayed reaction time and timing difference in between-hands finger pairings than in within-a-hand finger pairings. Such bimanual advantage of the pairings with two symmetric fingers was evident only in the task types with relatively high amplitudes. However, for a given finger pairing, the asymmetric amplitude configuration, assigning a relatively higher amplitude to either left or right finger of paired fingers, has no significant effect on the interfinger synchronization. Therefore, paired fingers on both hands showed a bimanual advantage in the relatively high force, especially for the pairing of symmetrical fingers, whereas asymmetric amplitude configuration for a finger pairing was able to suppress the bimanual advantage. These findings would enrich the understanding of the interfinger synchronization capability of paired fingers and be referential for interactive engineering applications when leveraging the interfinger synchronization capability in discrete fine-force control tasks.