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Matthew K. Seeley, Seong Jun Son, Hyunsoo Kim, and J. Ty Hopkins

Context: Patellofemoral pain (PFP) is often categorized by researchers and clinicians using subjective self-reported PFP characteristics; however, this practice might mask important differences in movement biomechanics between PFP patients. Objective: To determine whether biomechanical differences exist during a high-demand multiplanar movement task for PFP patients with similar self-reported PFP characteristics but different quadriceps activation levels. Design: Cross-sectional design. Setting: Biomechanics laboratory. Participants: A total of 15 quadriceps deficient and 15 quadriceps functional (QF) PFP patients with similar self-reported PFP characteristics. Intervention: In total, 5 trials of a high-demand multiplanar land, cut, and jump movement task were performed. Main Outcome Measures: Biomechanics were compared at each percentile of the ground contact phase of the movement task (α = .05) between the quadriceps deficient and QF groups. Biomechanical variables included (1) whole-body center of mass, trunk, hip, knee, and ankle kinematics; (2) hip, knee, and ankle kinetics; and (3) ground reaction forces. Results: The QF patients exhibited increased ground reaction force, joint torque, and movement, relative to the quadriceps deficient patients. The QF patients exhibited: (1) up to 90, 60, and 35 N more vertical, posterior, and medial ground reaction force at various times of the ground contact phase; (2) up to 4° more knee flexion during ground contact and up to 4° more plantarflexion and hip extension during the latter parts of ground contact; and (3) up to 26, 21, and 48 N·m more plantarflexion, knee extension, and hip extension torque, respectively, at various times of ground contact. Conclusions: PFP patients with similar self-reported PFP characteristics exhibit different movement biomechanics, and these differences depend upon quadriceps activation levels. These differences are important because movement biomechanics affect injury risk and athletic performance. In addition, these biomechanical differences indicate that different therapeutic interventions may be needed for PFP patients with similar self-reported PFP characteristics.

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Sean Sanford, Mingxiao Liu, and Raviraj Nataraj

Context: Continuous visual feedback (VF) can improve abilities to achieve desired movements and maximize rehabilitation outcomes by displaying actual versus target body positions in real time. Bandwidth VF reduces the reliance on feedback by displaying movement cues only when performance errors exceed specified thresholds. As such, bandwidth VF may better train independent movement abilities through greater development of intrinsic body control. In this study, continuous and bandwidth VF were investigated across modes of display (abstract and representative) that differed in body-discernibility. Objective: To compare the performance of the 2-legged squat during training with concurrent feedback (real-time VF) and short-term retention (immediately after training, VF removed). Design: Cross-sectional. Setting: University research laboratory. Participants: Eighteen healthy individuals. Methods: Marker-based motion capture displayed real-time position. Main Outcome Measures: Four VF cases (continuous–abstract, bandwidth–abstract, continuous–representative, and bandwidth–representative) were evaluated for accuracy and consistency to a target trajectory and target depth. Results: During training, both continuous VF cases showed significantly (P < .05) higher accuracy and consistency to the target trajectory compared with both bandwidth VF cases. Bandwidth VF resulted in greater potential learning (retention performance relative to a training baseline) compared with continuous–abstract. Conclusions: Continuous–representative may offer unique performance benefits in both training and retention of multisegment movement tasks. Bandwidth VF showed greater potential for learning. For long-term learning, an optimal VF paradigm should consider continuous–representative with bandwidth features.

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Gabriella Whitcomb-Khan, Nick Wadsworth, Kristin McGinty-Minister, Stewart Bicker, Laura Swettenham, and David Tod

This study explored the experiences of elite athletes during the initial stages of lockdown as a result of the COVID-19 pandemic. The eight recruited participants (three females, five males) were asked to tell a story of their lockdown experience. Narrative analysis was used to explore the athletes’ stories. The athletes’ narrative is best represented in four distinct sections: (a) threat to goals, (b) ongoing consequences, (c) overcoming COVID-19, and (d) adapting to COVID-19. Four narrative themes were also coconstructed from the athletes’ stories: (a) factors athletes found challenging, (b) loss, (c) strategies that benefitted athletes psychologically, and (d) silver linings. Combined, these findings suggest that the initial stages of lockdown are best described as a critical pause. The authors present applied implications for athletes and sport psychology practitioners. The authors also recommend that future research investigate the longitudinal effect of prolonged lockdown on athletes’ lives and a potential return to sport.

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Pablo Fanlo-Mazas, Elena Bueno-Gracia, Alazne Ruiz de Escudero-Zapico, Carlos López-de-Celis, César Hidalgo-García, Jacobo Rodríguez-Sanz, and María Orosia Lucha-López

Context: Localized and widespread hyperalgesia has been observed in patients with patellofemoral pain. Diacutaneous fibrolysis (DF) has shown to be effective in reducing pain in several musculoskeletal conditions including patellofemoral pain syndrome, but no studies have evaluated the effects of this technique in reducing localized and widespread hyperalgesia. Objective: To assess the effect of DF on the pressure pain threshold and muscle length tests in patients with patellofemoral pain syndrome. Design: A single-group, pretest–posttest clinical trial. Setting: University of Zaragoza. Participants: Forty-six subjects with patellofemoral pain (20 males and 26 females: age 27.8 [6.9] y). Intervention: Three sessions of DF. Main Outcome Measures: Pressure pain threshold using a handheld pressure algometer (4 sites around the knee, on tibialis anterior muscle, and one remote site on the upper contralateral limb); muscle length test of the iliotibial band, rectus femoris, and hamstring muscles; and patient-perceived treatment effect score. Results: The application of 3 sessions of DF significantly increased the pressure pain threshold in all sites at posttreatment evaluation (P < .001) and at a 1-week follow-up (P < .001). A significant increase in muscle length was also observed at the posttreatment evaluation (P < .001) and 1-week follow-up (P < .001). Ninety-seven percent of the patients reported subjective improvement at posttreatment and at 1-week follow-up. Conclusion: This study found that local and widespread hyperalgesia was significantly reduced after 3 sessions of diacutaneous fibrolysis and at the 1-week follow-up. A significant improvement on muscle length tests was also observed, with high clinical satisfaction among patients.

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Hyeonho Yu, Pamela H. Kulinna, and Shannon C. Mulhearn

Background: Environmental provisions can boost students’ discretionary participation in physical activity (PA) during lunchtime at school. This study investigated the effectiveness of providing PA equipment as an environmental intervention on middle school students’ PA levels and stakeholders’ perceptions of the effectiveness of equipment provisions during school lunch recess. Methods: A baseline–intervention research design was used in this study with a first baseline phase followed by an intervention phase (ie, equipment provision phase). A total of 514 students at 2 middle schools (school 1 and school 2) in a rural area of the western United States were observed directly using the System for Observing Play and Leisure Activity in Youth instrument. Interviews were conducted with stakeholders. Paired-sample t tests and visual analysis were conducted to explore differences in PA levels by gender, and common comparison (with trustworthiness measures) was used with the interview data. Results: The overall percentage of moderate to vigorous PA levels was increased in both schools (ranging from 8.0% to 24.0%). In school 2, there was a significant difference in seventh- and eighth-grade students’ moderate to vigorous PA levels from the baseline. Three major themes were identified: (1) unmotivated, (2) unequipped, and (3) unquestionable changes (with students becoming more active). Conclusions: Environmental supports (access, equipment, and supervision) significantly and positively influenced middle school students’ lunchtime PA levels.

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Danilo Fernandes da Silva, Shuhiba Mohammad, Taniya Singh Nagpal, Sara Carolina Scremin Souza, Rachel C. Colley, and Kristi Bree Adamo

Background: The authors examined whether or not ≤3 days wearing Actical® accelerometers provided acceptable results in comparison with the recommendation of ≥4 days in women across gestation. Methods: A total of 26, 76, and 57 participants at early, mid, and late pregnancy, respectively, were assessed. Participants were instructed to wear the device for 7 days and women who wore it for ≥4 days were included. For each participant, 3, 2, and 1 day(s) were randomly selected. Paired comparisons, intraclass correlations coefficients, and kappa statistics were performed for ≥4 days (criterion) versus 3, 2, and 1 day(s). Averages (in minutes per day) of sedentary time, light, moderate, vigorous, moderate to vigorous physical activity (PA) and steps per day were examined. Results: When 3 valid days were compared with the criterion, no significant differences were found for any gestational period. The intraclass correlations coefficients were “high” for all PA-related variables. The k values varied from .819 to .838 across pregnancy (“strong”). Two and 1 valid day(s) versus the criterion showed significant differences in some PA intensities, reduced intraclass correlations coefficients, “moderate” k values for 2 valid days (.638–.788) and “minimal-to-moderate” k values for 1 valid day (.367–.755). Conclusion: In pregnant women during early, mid, and late pregnancy, PA data obtained from 3 valid days of wear was equivalent and agreed with ≥4 valid days.

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Laura Prieto, Michael L. Norris, and Luis Columna

The purpose of this study was to examine the experiences of people with Parkinson’s (PwP) and their care partners (CPs) who participated in a Parkinson’s-focused community dance class in a northeastern state of the United States. In this qualitative inquiry, participants included five PwP and their respective CPs (n = 5). Three major, recurrent, and interrelated themes emerged from the data. These themes were (a) keep moving, (b) compassion in action, and (c) acceptance and freedom in dance. These themes captured personal and environmental factors that influenced the participation of PwP and their CPs in a dance class and how they perceived that dance influenced their quality of life. The themes described the obstacles, motives, and perceived outcomes of participating in dance. The findings emphasize the need for future dance interventions and programs that consider the CPs’ role in promoting participation for PwP in dance classes.

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Kyoungyoun Park-Braswell, Sandra J. Shultz, and Randy J. Schmitz

Context: Greater anterior knee laxity (AKL) is associated with impaired sensory input and decreased functional knee stability. As functional magnetic resonance imaging (MRI) is the gold standard for understanding brain function, methods to load the anterior cruciate ligament in the MRI environment could further our understanding of the ligament’s sensory role in knee joint stability. Objective: To design and validate an MRI-compatible anterior knee joint loading device. Design: Descriptive laboratory study. Setting: University laboratory study. Participants: Sixteen healthy and physically active females participated (age = 23.4 [3.7] y; mass = 64.4 [8.4] kg). Interventions: The AKL was assessed by a commercially available arthrometer. The AKL was also assessed with a custom-made, MRI-compatible device that produced anterior knee joint loading in a manner similar to the commercial arthrometer while obtaining dynamic structural MRI data. Main Outcome Measurements: The AKL (in millimeters) at 133 N of loading was assessed with the commercial knee arthrometer. Anterior displacement of the tibia relative to the femur obtained at 133 N of loading was measured from dynamic MRI data obtained during usage of the custom device. Pearson correlations were used to examine relationships between the 2 measures. The 95% limits of agreement compared the absolute differences between the 2 devices. Results: There was a 3.2-mm systematic difference between AKL (6.3 [1.6] mm) and anterior tibial translation (3.2 [1.0] mm) measures. There was a significant positive correlation between values obtained from the commercial arthrometer and the MRI-compatible device values (r = .553, P = .026). Conclusions: While systematic differences were observed, the MRI-compatible anterior knee joint loading device anteriorly translated the tibia relative to the femur in a similar manner to a commercial arthrometer design to stress the anterior cruciate ligament. Such a device may be beneficial in future functional magnetic resonance imaging study of anterior cruciate ligament mechanoreception.