ACUTE EFFECTS OF FOOTWEAR AND FOOTSTRIKE PATTERN ON ACHILLES TENDON LOADING DURING RUNNING

The study aimed to investigate the effect of footwear and foot strikes on Achilles tendon (AT) loading during running. Eleven male recreational runners with rearfoot strike pattern were recruited. The ground reaction force, kinematics, and kinetics of the ankle joint at 10 km/h were collected using an instrumented split-belt treadmill and a motion capture system. The morphological and mechanical characteristics of AT were recorded and calculated with a synchronous ultrasonic imaging instrument. The results showed a significantly greater peak AT force in minimalist shoes and forefoot strike pattern. The peak force and length change of the AT significantly increased when forefoot striking. It suggested that immediate use of minimalist shoes and/or transitioning to forefoot strike could provide higher tendon loading intensity to improve the loading characteristics of the AT

EFFECTS OF 12-WEEK GAIT RETRAINING ON THE MORPHOLOGY OF MEDIAL GASTROCNEMIUS

The purpose of this study was to investigate the effects of 12-week gait retraining on the morphological properties of medial gastrocnemius. Thirty-four male habitual rearfoot strike runners were recruited and randomized divided into gait training group and control group. The medial gastrocnemius morphological properties were measured using an ultrasound device before and after training. A two-way repeated measures ANOVA (group × time) was used for analysis. The significance level was set as 0.05. The results found that after 12-week gait retraining, there was no significant group main effect and interaction effect for all parameters. A main effect of time was observed in the fascicle length (p = 0.016) and normalized fascicle length (p = 0.026). After training, the fascicle length for the GR and CON groups significantly increased by 8.5% (GR) and 2.2% (CON), and the normalized fascicle length increased by 8.8% (GR) and 2.0% (CON). It was indicated that both gait retraining and running training effectively increase the fascicle length of the medial gastrocnemius, thereby providing potential means of increasing the velocity of muscle contraction and reducing the risk of a calf strain while running

EFFECTS OF HABITUAL FOOT STRIKE PATTERNS ON ANKLE MUSCLES ACTIVATION DURING RUNNING

This study aimed to determine differences in muscle activation between habitual rearfoot strike pattern (RFS) and non-rearfoot strike pattern (NRFS) runners. Ten habitual RFS and ten habitual NRFS runners were recruited in this study. The electromyography signals were collected from the tibialis anterior, soleus, medial and lateral gastrocnemius muscles at 9 km/h running. The root mean square of each muscle and the co-activation of ankle flexors and extensors (COAnkle) were calculated. Independent t-tests or nonparametric tests were used to examine the differences between two groups. The results showed that during the pre-activation and swing phases, the COAnkle of RFS runners were greater than those of NRFS runners. This suggested that RFS runners with higher COAnkle at pre-activation might be a strategy in response to great impact force during the early of stance

ACUTE EFFECTS OF FOOT STRIKE PATTERN TRANSITION ON TRICEPS SURAE AND TIBIALIS ANTERIOR MUSCLE ACTIVITIES DURING RUNNING

This study aimed to investigate the acute effects of transitioning foot strike patterns on muscle activity in the lateral gastrocnemius (LG), medial gastrocnemius (MG), soleus (SOL), and tibialis anterior (TA) muscles during running. Fifteen healthy male runners with habitual rearfoot strike pattern (RFS) were recruited to complete running with RFS and the forefoot strike pattern (FFS) tests at 9 km/h. The electromyography (EMG) and ground reaction force were collected synchronously. The paired t-tests were used to examine the differences in the root mean square (RMS) between FFS and RFS. The results revealed that the mean RMS for the triceps surae was higher in FFS than in RFS and the muscle co-activation ratio was higher in RFS than in FFS during the pre-activation phase. In conclusion, the acute transitioning to FFS could change muscle activation mode during running

Morphological and viscoelastic properties of the Achilles tendon in the forefoot, rearfoot strike runners, and non-runners in vivo

The purpose of this study was to investigate the differences in the morphological and viscoelastic properties of the Achilles tendon (AT) among different groups (rearfoot strikers vs. forefoot strikers vs. non-runners). Thirty healthy men were recruited, including habitual forefoot strike runners (n = 10), rearfoot strike runners (n = 10), and individuals with no running habits (n = 10). The AT morphological properties (cross-sectional area and length) were captured by using an ultrasound device. The real-time ultrasound video of displacement changes at the medial head of the gastrocnemius and the AT junction during maximal voluntary isometric contraction and the plantar flexion moment of the ankle was obtained simultaneously by connecting the ultrasound device and isokinetic dynamometer via an external synchronisation box. The results indicated that male runners who habitually forefoot strike exhibited significantly lower AT hysteresis than male non-runners (p < 0.05). Furthermore, a greater peak AT force during maximal voluntary contraction was observed in forefoot strike male runners compared to that in male individuals with no running habits (p < 0.05). However, foot strike patterns were not related to AT properties in recreational male runners (p > 0.05). The lower AT hysteresis in male FFS runners implied that long-term forefoot strike patterns could enhance male-specific AT’s ability to store and release elastic energy efficiently during running, resulting in a more effective stretch-shortening cycle. The greater peak AT force in male FFS runners indicated a stronger Achilles tendon

Mediating effect of rehabilitation self-efficacy on perceived social support and rehabilitation exercise adherence in hospitalized patients after hip/knee arthroplasty

Objective·To explore the correlation among perceived social support, rehabilitation self-efficacy and rehabilitation exercise adherence of in-patients after hip/knee arthroplasty, and examine the mediating role of rehabilitation self-efficacy in the correlation between perceived social support and rehabilitation exercise adherence.Methods·A convenience sampling method was used, and 141 post-total hip/knee arthroplasty inpatients in the bone and joint ward of the First Affiliated Hospital of Naval Medical University (Shanghai Changhai Hospital) from October 2021 to February 2023 were selected as the study subjects. The general demographic data, such as age and gender, and the information of disease and operation were assessed by using General Data Questionnaire. The adherence to rehabilitation exercise in patients after hip/knee arthroplasty was assessed by using the Rehabilitation Exercise Adherence Scale (REAS); the self-efficacy of rehabilitation exercise was assessed by using the Self-Efficacy for Rehabilitation Outcome Scale (SER); the social support level of individual subjective feelings of the patients was assessed by using the Perceived Social Support Scale (PSSS). Pearson's correlation analysis was used to test the correlation between the variables, and Bootstrap method was used to investigate the mediating role of rehabilitation self-efficacy in the correlation between perceived social support and rehabilitation exercise adherence.Results·A total of 167 questionnaires were distributed and 141 valid questionnaires were recovered, with a valid recovery rate of 84.4%. The age range of the 141 patients after hip/knee arthroplasty was 26‒84 years old, and the average age was (64.75±10.74) years old. The total score of SER of the patients after hip/knee arthroplasty was (100.45±21.71), the total score of PSSS was (68.29±10.89), and the total score of REAS was (11.93±2.29). Pearson's correlation analysis results showed that there was a significant correlation between SER score and PSSS score, SER score and REAS score, and PSSS score and REAS score in patients after hip/knee arthroplasty. The mediation effect analysis showed that the indirect effect of perceived social support on rehabilitation exercise adherence was significant (effect value 0.033, 95%CI 0.017‒0.058, P0.05).Conclusion·Perceived social support positively predicts rehabilitation exercise adherence, and rehabilitation self-efficacy fully mediates the correlation. Direct intervention in rehabilitation self-efficacy is superior to moderating the level of perceived social support

Effects of 12-week gait retraining on plantar flexion torque, architecture, and behavior of the medial gastrocnemius in vivo

Objective:This study aims to explore the effects of 12-week gait retraining (GR) on plantar flexion torque, architecture, and behavior of the medial gastrocnemius (MG) during maximal voluntary isometric contraction (MVIC).Methods:Thirty healthy male rearfoot strikers were randomly assigned to the GR group (n = 15) and the control (CON) group (n = 15). The GR group was instructed to wear minimalist shoes and run with a forefoot strike pattern for the 12-week GR (3 times per week), whereas the CON group wore their own running shoes and ran with their original foot strike pattern. Participants were required to share screenshots of running tracks each time to ensure training supervision. The architecture and behavior of MG, as well as ankle torque data, were collected before and after the intervention. The architecture of MG, including fascicle length (FL), pennation angle, and muscle thickness, was obtained by measuring muscle morphology at rest using an ultrasound device. Ankle torque data during plantar flexion MVIC were obtained using a dynamometer, from which peak torque and early rate of torque development (RTD50) were calculated. The fascicle behavior of MG was simultaneously captured using an ultrasound device to calculate fascicle shortening, fascicle rotation, and maximal fascicle shortening velocity (Vmax).Results:After 12-week GR, 1) the RTD50 increased significantly in the GR group (p = 0.038), 2) normalized FL increased significantly in the GR group (p = 0.003), and 3) Vmax increased significantly in the GR group (p = 0.018).Conclusion:Compared to running training, GR significantly enhanced the rapid strength development capacity and contraction velocity of the MG. This indicates the potential of GR as a strategy to improve muscle function and mechanical efficiency, particularly in enhancing the ability of MG to generate and transmit force as well as the rapid contraction capability. Further research is necessary to explore the effects of GR on MG behavior during running in vivo

A review of uphill and downhill running: biomechanics, physiology and modulating factors

Graded running imposes distinct biomechanical and physiological demands compared with level running, which influences performance outcomes and injury risk. Uphill running requires great propulsion and energy expenditure, which results in increased oxygen consumption and cardiovascular burden. By contrast, downhill running relies heavily on eccentric muscle contractions, which show an association with great fatigue and a high risk of injury. This review aims to summarize biomechanical and physiological adaptations to uphill and downhill running and evaluate the mechanisms underlying the interaction of modulating factors (footwear, foot strike patterns, individual characteristics, pacing strategies, cadence and running speed) with slope. Based on current evidence, these factors affect mechanical loading, energy cost and neuromuscular responses during uphill and downhill running. Footwear design, especially carbon-fiber plate shoes, can reduce metabolic cost during uphill and downhill running. Forefoot striking reduces peak impact forces compared to rearfoot striking, especially in downhill running, helping to lower impact on the lower limbs. Individual factors, like training level, influence the effectiveness of these factors, with experienced runners adapting better to slopes. Additionally, adjusting cadence can reduce per-step load and energy expenditure during uphill and downhill running. Although considerable progress has been made, further research still necessitates the exploration of graded running in real-world environments, improvement of training methods, clarification of the interactions between various factors and slope and optimization of methods to prevent injuries

Advanced lung cancer inflammation index is associated with prognosis in skin cancer patients: a retrospective cohort study

BackgroundSkin cancer ranks as one of the most prevalent malignant tumors affecting humans. This study was designed to explore the correlation between the advanced lung cancer inflammation index (ALI), a metric that gauged both nutrition and inflammation statuses, in skin cancer patients and their subsequent prognosis.MethodsData from the National Health and Nutrition Examination Survey (NHANES) spanning 1999-2018 were scrutinized, along with mortality tracking extending to December 31, 2019. Kaplan-Meier survival curves and COX regression analysis, utilizing NHANES-recommended weights, delineated the association between ALI levels and skin cancer prognosis. To decipher the potential non-linear relationship, a restricted cubic spline analysis was applied. Additionally, stratified analysis was conducted to affirm the robustness of our findings.ResultsThe 1,149 patients participating in NHANES 1999-2018 were enrolled. We observed a reverse J-shaped non-linear relationship between ALI and both skin cancer all-cause mortality and cancer mortality, with inflection points at 81.13 and 77.50, respectively.ConclusionsThe ALI served as a comprehensive indicator of a patient’s nutrition and inflammation status and was demonstrably linked to the prognosis in skin cancer cases. The meticulous evaluation and continuous monitoring of these parameters in skin cancer patients bear clinical importance