Browse

You are looking at 51 - 60 of 24,887 items

Restricted access

Jacinta M. Saldaris, Grant J. Landers and Brendan S. Lay

Purpose: To examine the effects of precooling via crushed ice ingestion on cognitive function during exercise in the heat. Methods: Eleven active men ingested either 7 g·kg−1 of crushed ice (ICE) or thermoneutral water (CON) 30 minutes before running 90 minutes on a treadmill at a velocity equivalent to 65% VO2peak in hot and humid conditions (35.0°C [0.5°C], 53.1% [3.9%] relative humidity). Participants completed 3 cognitive tasks to investigate decision making (8-choice reaction time [CRT]), working memory (serial seven [S7]), and executive control (color multisource interference task [cMSIT]) on arrival, after precooling, and after running. Results: Precooling significantly decreased preexercise core (T core) and forehead skin temperature in ICE compared with CON, respectively (T core 0.8°C [0.4°C], –0.2°C [0.1°C]; T head –0.5°C [0.4°C], 0.2°C [0.8°C]; P ≤ .05). Postrun, ICE significantly reduced errors compared with CON for CRT (P ≤ .05; d = 0.90; 90% confidence interval, 0.13–1.60) and S7 (P ≤ .05; d = 1.05; 90% confidence interval, 0.26–1.75). Thermal sensation was lower after precooling with ICE (P ≤ .05), but no significant differences were recorded between conditions for cMSIT errors, skin temperature, heart rate, or ratings of perceived exertion or perceived thirst (P > .05). Conclusions: Precooling via ICE maintained cognitive accuracy in decision making and working memory during exercise in the heat. Thus, ICE may have the potential to improve sporting performance by resisting deleterious effects of exercise in a hot and humid environment on cognitive function.

Restricted access

Marcie Fyock, Nelson Cortes, Alex Hulse and Joel Martin

Clinical Scenario: Patellofemoral pain (PFP) is a common knee injury in recreational adult runners, possibly caused by faulty mechanics. One possible approach to reduce this pain is to retrain the runner’s gait. Current research suggests that no definitive gold standard treatment for PFP exists. Gait retraining utilizing visual feedback may reduce PFP in both the short and long term. Clinical Question: In adult runners diagnosed with PFP, does gait retraining with real-time visual feedback lead to a decrease in pain? Summary of Key Findings: A literature search was performed; 3 relevant studies utilizing gait retraining with visual feedback, pain level as an outcome measure, and follow-up measures of at least 1 month after the intervention were included. All the included studies reported a decrease in short- and long-term pain for participants following visual feedback gait retraining. In addition, biomechanical measures related to PFP, including peak hip adduction angle and the angle of contralateral pelvic drop, improved after the completion of the intervention. Clinical Bottom Line: There is level 2 evidence supporting the implementation of 8 sessions over 2 weeks of visual feedback gait retraining as a means of treating patients diagnosed with PFP. Based on current available evidence, clinicians should identify faulty mechanics of patients and implement a protocol of increasing real-time visual feedback over the first 4 sessions and decreasing visual feedback over the final 4 sessions. Strength of Recommendation: Level 2.

Restricted access

Mark S. Tremblay

Background: Emerging research shows that the composition of movement behaviors throughout the day (physical activities, sedentary behaviors, sleep) is related to indicators of health, suggesting previous research that isolated single movement behaviors maybe incomplete, misleading, and/or unnecessarily constrained. Methods: This brief report summarizes evidence to support a 24-hour movement behavior paradigm and efforts to date by a variety of jurisdictions to consult, develop, release, promote, and study 24-hour movement guidelines. It also introduces and summarizes the accompanying series of articles related specifically to 24-hour movement guidelines for the early years. Results: Using robust and transparent processes, Canada, Australia, New Zealand, South Africa, and the World Health Organization have developed and released 24-hour movement guidelines for the early years: an integration of physical activity, sedentary behavior, and sleep. Other countries are exploring a similar approach and related research is expanding rapidly. Articles related to guideline development in South Africa, the United Kingdom, Australia, and by the World Health Organization are a part of this special series. Conclusions: A new paradigm employing 24-hour movement guidelines for the early years that combines recommendations for movement behaviors across the whole day is gaining momentum across the globe.

Restricted access

Nicola Marotta, Andrea Demeco, Gerardo de Scorpio, Angelo Indino, Teresa Iona and Antonio Ammendolia

Context: Activation time of the quadriceps is important in determining injury risk in professional soccer players. Objective: To compare the activation time of the quadriceps and hamstrings muscles during a movement that puts stress on anterior cruciate ligament (ACL) to assess the risk of ACL injury. Design: Case series. Setting: University laboratory for movement analysis. Patients or Other Participants: Twenty (10 males and 10 females) professional soccer players. Intervention(s): An inertial sensor and 4 electrodes positioned on the quadriceps and hamstrings muscles were used for the surface electromyography. The athlete resting on 1 leg dropped, from a 32-cm-high platform, on the suspended foot (testing leg), without jumping or lowering his center of gravity and maintaining single-leg landing for 5 seconds. Using a software, it is possible to calculate the activation time of the rectus femoris, vastus medialis (VM), biceps femoris, and semimembranosus muscles before ground contact. Main Outcome Measures: To evaluate the activation times of the rectus femoris, VM, biceps femoris, and semitendinosus muscles before ground contact in comparison with the range of normality calculated by the manufacturer. Results: All male soccer players demonstrated a low risk related to the correct activation of all the examined muscles, while female soccer players demonstrated delayed activation of the VM. Conclusions: Delayed activation of the VM registered in females determines an increase in anterior shear force, which is an important risk factor for incurring an ACL injury. This testing protocol becomes adequate for the screening of high-risk athletes and for targeting interventions to specific imbalances that may increase injury risk.

Restricted access

Theresa C. Hauge, Garrett E. Katz, Gregory P. Davis, Kyle J. Jaquess, Matthew J. Reinhard, Michelle E. Costanzo, James A. Reggia and Rodolphe J. Gentili

Few studies have examined high-level motor plans underlying cognitive-motor performance during practice of complex action sequences. These investigations have assessed performance through fairly simple metrics without examining how practice affects the structures of action sequences. By adapting the Levenshtein distance (LD) method to the motor domain, we propose a computational approach to accurately capture performance dynamics during practice of action sequences. Practice performance dynamics were assessed by computing the LD based on the number of insertions, deletions, and substitutions of actions needed to transform any sequence into a reference sequence (having a minimal number of actions to complete the task). Also, combining LD-based performance with mental workload metrics allowed assessment of cognitive-motor efficiency dynamics. This approach was tested on the Tower of Hanoi task. The findings revealed that throughout practice this method could capture: i) action sequence performance improvements as indexed by a reduced LD (decrease of insertions and substitutions), ii) structural modifications of the high-level plans, iii) an attenuation of mental workload, and iv) enhanced cognitive-motor efficiency. This effort complements prior work examining the practice of complex action sequences in healthy adults and has potential for probing cognitive-motor impairment in clinical populations as well as the development/assessment of cognitive robotic controllers.

Restricted access

Dinesh John, Qu Tang, Fahd Albinali and Stephen Intille

Background: Physical behavior researchers using motion sensors often use acceleration summaries to visualize, clean, and interpret data. Such output is dependent on device specifications (e.g., dynamic range, sampling rate) and/or are proprietary, which invalidate cross-study comparison of findings when using different devices. This limits flexibility in selecting devices to measure physical activity, sedentary behavior, and sleep. Purpose: Develop an open-source, universal acceleration summary metric that accounts for discrepancies in raw data among research and consumer devices. Methods: We used signal processing techniques to generate a Monitor-Independent Movement Summary unit (MIMS-unit) optimized to capture normal human motion. Methodological steps included raw signal harmonization to eliminate inter-device variability (e.g., dynamic g-range, sampling rate), bandpass filtering (0.2–5.0 Hz) to eliminate non-human movement, and signal aggregation to reduce data to simplify visualization and summarization. We examined the consistency of MIMS-units using orbital shaker testing on eight accelerometers with varying dynamic range (±2 to ±8 g) and sampling rates (20–100 Hz), and human data (N = 60) from an ActiGraph GT9X. Results: During shaker testing, MIMS-units yielded lower between-device coefficient of variations than proprietary ActiGraph and ENMO acceleration summaries. Unlike the widely used ActiGraph activity counts, MIMS-units were sensitive in detecting subtle wrist movements during sedentary behaviors. Conclusions: Open-source MIMS-units may provide a means to summarize high-resolution raw data in a device-independent manner, thereby increasing standardization of data cleaning and analytical procedures to estimate selected attributes of physical behavior across studies.

Restricted access

Andreas Heissel, Anou Pietrek, Michael A. Rapp, Stephan Heinzel and Geoffrey Williams

The role of perceived need support from exercise professionals in improving mental health was examined in a sample of older adults, thereby validating the short Health Care Climate Questionnaire. A total of 491 older people (M = 72.68 years; SD = 5.47) attending a health exercise program participated in this study. Cronbach’s alpha was found to be high (α = .90). Satisfaction with the exercise professional correlated moderately with the short Health Care Climate Questionnaire mean value (r = .38; p < .01). The mediator analyses yielded support for the self-determination theory process model in older adults by showing both basic need satisfaction and frustration as mediating variables between perceived autonomy support and depressive symptoms. The short Health Care Climate Questionnaire is an economical instrument for assessing basic need satisfaction provided by the exercise therapist from the participant’s perspective. Furthermore, this cross-sectional study supported the link from coaching style to the satisfaction/frustration of basic psychological needs, which in turn, predicted mental health. Analyses of criterion validity suggest a revision of the construct by integrating need frustration.

Restricted access

Frank E. DiLiberto and Deborah A. Nawoczenski

Although the midfoot is recognized to have an important role in the successful performance of a single-limb heel rise, healthy heel rise performance remains primarily characterized by ankle function. The purpose of this study was to examine the contribution of midfoot region power to single-limb heel rise in healthy adults. Participants (N = 12) performed 20 single-limb heel rises. An electromagnetic motion capture system and a force plate were used to record 3-segment foot motion and ground reaction forces. Inverse dynamic calculations were performed to obtain ankle and midfoot region powers. These data were evaluated with descriptive statistics. A correlation was performed to evaluate the contribution of midfoot region power to heel height, as heel height is a clinical measure of heel-rise performance. The midfoot contributed power during single-limb heel rise (peak positive power: 0.5 [0.2] W·kg−1). Furthermore, midfoot peak power accounted for 36% of the variance in heel height (P = .04). As energy generating internal mechanisms, such as muscle activity, are attributed to power generation, midfoot tissue loading and muscle performance should be considered during clinical and modeling applications of the heel-rise task.

Restricted access

Marlowe Pecora, Luc Tremblay and Matthew Heath

Reaches with overlapping stimulus-response spatial relations (propointing) adhere to speed–accuracy relations as defined by Paul Fitts’ index of difficulty equation (IDFitts: in bits of information). This movement principle is attributed to response mediation via the “fast” visuomotor networks of the dorsal visual pathway. It is, however, unclear whether the executive demands of dissociating stimulus-response spatial relations by reaching mirror-symmetrical to a target (antipointing) elicits similar adherence to Fitts’ equation. Here, pro- and antipointing responses were directed to a constant target amplitude with varying target widths to provide IDFitts values of 3.0, 3.5, 4.3, and 6.3 bits. Propointing movement times linearly increased with IDFitts—a result attributed to visually based trajectory corrections. In contrast, antipointing movement times, deceleration times, and endpoint precision did not adhere to Fitts’ equation. These results indicate that antipointing renders a “slow” and offline mode of control mediated by the visuoperceptual networks of the ventral visual pathway.

Restricted access

Elroy J. Aguiar, Zachary R. Gould, Scott W. Ducharme, Chris C. Moore, Aston K. McCullough and Catrine Tudor-Locke

Background: A walking cadence of ≥100 steps/min corresponds to minimally moderate intensity, absolutely defined as ≥3 metabolic equivalents (METs). This threshold has primarily been calibrated during treadmill walking. There is a need to determine the classification accuracy of this cadence threshold to predict intensity during overground walking. Methods: In this laboratory-based cross-sectional investigation, participants (N = 75, 49.3% women, age 21–40 y) performed a single 5-minute overground (hallway) walking trial at a self-selected preferred pace. Steps accumulated during each trial were hand tallied and converted to cadence (steps/min). Oxygen uptake was measured using indirect calorimetry and converted to METs. The classification accuracy (sensitivity, specificity, overall accuracy, and positive predictive value) of ≥100 steps/min to predict ≥3 METs was calculated. Results: A cadence threshold of ≥100 steps/min yielded an overall accuracy (combined sensitivity and specificity) of 73.3% for predicting minimally moderate intensity. Moreover, for individuals walking at a cadence ≥100 steps/min, the probability (positive predictive value) of achieving minimally moderate intensity was 80.3%. Conclusions: Although primarily developed using treadmill-based protocols, a cadence threshold of ≥100 steps/min for young adults appears to be a valid heuristic value (evidence-based, rounded, practical) associated with minimally moderate intensity during overground walking performed at a self-selected preferred pace.