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Despite the widespread use of the OptoGait photoelectric cell system for the analysis of running spatiotemporal parameters, its reliability has not been proved. Consequently, this study intends to determine the test–retest reliability of the system when applied to treadmill running spatiotemporal parameters and lower body stiffness at a constant velocity. Amateur endurance runners (n = 31; age: 34.42 ± 9.26 years; height: 171.54 ± 9.15 cm; body mass: 66.63 ± 11.3 kg) voluntarily consented to participate in this study. Data for each participant were recorded twice per session across two testing sessions. The intra-session and inter-session reliabilities of spatiotemporal parameters and lower body stiffness were determined through test–retest analysis. Although mean comparisons revealed significant differences between measurements in spatiotemporal running gait characteristics and lower body stiffness for intra-session (p < 0.05 in all parameters), the effect size was always small (<0.4). Moreover, the relationship between measurements was very large for spatiotemporal parameters and lower body stiffness (r > 0.7). The intraclass correlation coefficients revealed an almost perfect correlation between measurements (intraclass correlation coefficients >0.81), except Kleg with substantial reliability (intraclass correlation coefficient = 0.788). The inter-session reliability revealed some significant differences in contact time (p = 0.009) and Kleg (p = 0.013), although Cohen’s d indicated small effect size (<0.31). The relationship between sessions was very large for spatiotemporal parameters and lower body stiffness (r > 0.8), and the intraclass correlation coefficients revealed an almost perfect inter-session association (intraclass correlation coefficients >0.881). The results found here show that the OptoGait system can be used confidently for running spatiotemporal parameters analysis and lower body stiffness at a constant velocity for healthy adults.

The aim of this study was twofold: (i) to analyze the physical demands in the return to play (RTP) process of high-level soccer players in the role of floater in different soccer sided games (SGs) formats (i.e., 4vs4 + 2 and 8vs8 + 1); and (ii) to analyze the differences in physical demands encountered by regular and floater players among the SGs formats and official matches by means of global positioning system technology (GPS APEX pod, North Ireland) was used. Twenty-six highly trained, male soccer players (U16 years) participated in this investigation. Players were classified into two groups: 23 regular and 3 floater players, a total of eight SGs were analyzed, which involved the recording of 80 observations of regular and floater players. Match-play players showed most likely–probable differences in distance covered at high-intensity per minute (D > 14.4/min), at high-speed running per minute (D > 21/min), and peak velocity (Vpeak) in comparison to floaters in the 8vs8 + 1 LSG (large-side-games), and presented most likely differences in accelerations >2/min in comparison to match-play players. Therefore, the use of floaters during the last phase of the RTP (return to play) seems to be a useful strategy for progressive reintroduction into specific training (1) floater in the 4vs4 + 2 SSG; (2) floater in the 8vs8 + 1 LSG; (3) regular player in the 4vs4 + 2 SSG; and (4) regular player in the 8vs8 + 1 LSG before starting full trainings and returning to competition.

Mechanical power may act as a key indicator for physiological and mechanical changes during running. In this scoping review, we examine the current evidences about the use of power output (PW) during endurance running and the different commercially available wearable sensors to assess PW. The Boolean phrases endurance OR submaximal NOT sprint AND running OR runner AND power OR power meter, were searched in PubMed, MEDLINE, and SCOPUS. Nineteen studies were finally selected for analysis. The current evidence about critical power and both power-time and power-duration relationships in running allow to provide coaches and practitioners a new promising setting for PW quantification with the use of wearable sensors. Some studies have assessed the validity and reliability of different available wearables for both kinematics parameters and PW when running but running power meters need further research before a definitive conclusion regarding its validity and reliability.

Background: The study of children with unilateral cerebral palsy (UCP) has traditionally focused on motor aspects. The extent to which sensory processing disorders can affect their functional performance and quality of life (QoL) is uncertain. This study aimed to explore the differences in sensory processing between UCP and typical development (TD) children and to analyze the relationship of sensory processing with functional performance and QoL. Methods: Fifty-three children aged from 6 to 15 years (TD = 24; UCP = 26) were recruited. The Child Sensory Profile 2, Pediatric Evaluation of Disability Inventory—Computer Adaptive Test and Kidscreen were used to evaluate sensory processing, functional performance and QoL. Results: UCP children showed sensory processing difficulties (avoidance: p = 0.02; registration: p = 0.00; body position: p = 0.00; oral: p = 0.02; social-emotional: p = 0.01), and scored lower in functional performance (daily activities: p = 0.00; mobility: p = 0.00; social/cognitive: p = 0.04) and in physical well-being (p = 0.00). The highest correlations in UCP group were found between proprioceptive processing and daily activities and mobility (r = −0.39); auditory, visual and tactile information and school environment (r = −0.63; r = −0.51; r = −0.46); behavioral and social-emotional responses and psychological well-being (r = −0.64; r = −0.49). Conclusions: UCP children have greater difficulty in sensory processing than TD children. Difficulties in proprioceptive processing contribute to poorer functional performance. Auditory, visual and tactile processing is associated with participation in the school environment and behavioral and social-emotional responses related to sensory processing are associated with the psychological well-being.

The use of markerless motion capture systems is becoming more popular for walking and running analysis given their user-friendliness and their time efficiency but in some cases their validity is uncertain. Here, the test-retest reliability of the MotionMetrix software combined with the use of Kinect sensors is tested with 24 healthy volunteers for walking (at 5 km·h−1) and running (at 10 and 15 km·h−1) gait analysis in two different trials. All the parameters given by the MotionMetrix software for both walking and running gait analysis are tested in terms of reliability. No significant differences (p > 0.05) were found for walking gait parameters between both trials except for the phases of loading response and double support, and the spatiotemporal parameters of step length and step frequency. Additionally, all the parameters exhibit acceptable reliability (CV < 10%) but step width (CV > 10%). When analyzing running gait, although the parameters here tested exhibited different reliability values at 10 km·h−1, the system provided reliable measurements for most of the kinematic and kinetic parameters (CV < 10%) when running at 15 km·h−1. Overall, the results obtained show that, although some variables must be interpreted with caution, the Kinect + MotionMetrix system may be useful for walking and running gait analysis. Nevertheless, the validity still needs to be determined against a gold standard system to fully trust this technology and software combination.

Wearable technology has allowed for the real-time assessment of mechanical work employed in several sporting activities. Through novel power metrics, Functional Threshold Power have shown a reliable indicator of training intensities. This study aims to determine the relationship between mean power output (MPO) values obtained during three submaximal running time trials (i.e., 10 min, 20 min, and 30 min) and the functional threshold power (FTP). Twenty-two recreationally trained male endurance runners completed four submaximal running time trials of 10, 20, 30, and 60 min, trying to cover the longest possible distance on a motorized treadmill. Absolute MPO (W), normalized MPO (W/kg) and standard deviation (SD) were calculated for each time trial with a power meter device attached to the shoelaces. All simplified FTP trials analyzed (i.e., FTP10, FTP20, and FTP30) showed a significant association with the calculated FTP (p < 0.001) for both MPO and normalized MPO, whereas stronger correlations were found with longer time trials. Individual correction factors (ICF% = FTP60/FTPn) of ~90% for FTP10, ~94% for FTP20, and ~96% for FTP30 were obtained. The present study procures important practical applications for coaches and athletes as it provides a more accurate estimation of FTP in endurance running through less fatiguing, reproducible tests.

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