Clinical Issues - May 2024.

Wearing shoe covers in the perioperative setting Key words: shoe covers, shoes, contamination, transmission, bacteria. Wearing eyelash extensions in the perioperative setting Key words: eyelash extensions, sterile field, bonding agent, eye infection, cosmetic products. Promoting health in the workplace Key words: health-promotion program, injury-prevention program, musculoskeletal, mindfulness, stretching. Releasing amputated limbs Key words: amputated limb release, specimen management, burial, cultural, religious.

Effects of gait retraining using minimalist shoes on the medial gastrocnemius muscle-tendon unit behavior and dynamics during running.

The effects of a 12-week gait retraining program on the adaptation of the medial gastrocnemius (MG) and muscle-tendon unit (MTU) were investigated. 26 runners with a rearfoot strike pattern (RFS) were randomly assigned to one of two groups: gait retraining (GR) or control group (CON). MG ultrasound images, marker positions, and ground reaction forces (GRF) were collected twice during 9 km/h of treadmill running before and after the intervention. Ankle kinetics and the MG and MTU behavior and dynamics were quantified. Runners in the GR performed gradual 12-week gait retraining transitioning to a forefoot strike pattern. After 12-week, (1) ten participants in each group completed the training; eight participants in GR transitioned to non-RFS with reduced foot strike angles; (2) MG fascicle contraction length and velocity significantly decreased after the intervention for both groups, whereas MG forces increased after intervention for both groups; (3) significant increases in MTU stretching length for GR and peak MTU recoiling velocity for both groups were observed after the intervention, respectively; (4) no significant difference was found for all parameters of the series elastic element. Gait retraining might potentially influence the MG to operate at lower fascicle contraction lengths and velocities and produce greater peak forces. The gait retraining had no effect on SEE behavior and dynamics but did impact MTU, suggesting that the training was insufficient to induce mechanical loading changes on SEE behavior and dynamics.

An innovative flat-knit compression garment for lymphoedema patients led to better outcomes: a multicentre study.

OBJECTIVE: To evaluate the clinical performance, quality of life (QoL) and patient satisfaction with an innovative flat-knit compression garment for the daytime treatment of lymphoedema patients in daily routine. METHOD: In a prospective multicentre observational study, patients with leg or arm lymphoedema (stage I-II, International Society of Lymphology (ISL) standards, 2016) received a made-to-measure flat-knit compression class 2 JOBST Confidence (BSN-JOBST GmbH, Germany) thigh-high stocking or arm sleeve. Primary endpoint was the oedema status as determined by the mean sum of the circumferences at the beginning and the end of the wearing period. Secondary endpoints included QoL-related parameters and patient satisfaction with product features assessed through questionnaires. The observation period lasted three weeks. RESULTS: A total of 97 patients (87 females, 10 males), of which 65 had leg lymphoedema and 32 had arm lymphoedema, received the study device. The oedema status was effectively maintained (slight reduction in mean sum of circumferences by -3.1±7.3cm; p=0.0001). For QoL-related parameters, the patients reported fewer limitations in work, leisure and psychological wellbeing after wearing the stocking or arm sleeve (all p-values <0.0001). They also experienced less limitations in function and movement, feeling of tension and heaviness, and fewer difficulties wearing clothes, shoes, jewellery or watches at study end (all p-values <0.0001). In terms of pleasant feeling on the skin, moisture management, softness of material, range of motion, overall wearing comfort and heat build-up under the garment, patients were more satisfied with the tested compression garment than with previously worn compression garments (all p-values <0.001). CONCLUSION: In this study, the tested innovative compression product increased patient satisfaction with the improved product features while the lymphoedema status was successfully maintained.

Real-world data capture of daily limb loading using force-sensing insoles: Feasibility and lessons learned.

Force-sensing insoles are wearable technology that offer an innovative way to measure loading outside of laboratory settings. Few studies, however, have utilized insoles to measure daily loading in real-world settings. This is an ancillary study of a randomized controlled trial examining the effect of weight loss alone, weight loss plus weighted vest, or weight loss plus resistance training on bone health in older adults. The purpose of this ancillary study was to determine the feasibility of using force-sensing insoles to collect daily limb loading metrics, including peak force, impulse, and loading rate. Forty-four participants completed a baseline visit of three, 2-minute walking trials while wearing force-sensing insoles. During month two of the intervention, 37 participants wore insoles for 4 days for 8 waking hours each day. At 6-month follow-up, participants completed three, two-minute walking trials and a satisfaction questionnaire. Criteria for success in feasibility was defined as: a) > 60 % recruitment rate; b) > 80 % adherence rate; c) > 75 % of usable data, and d) > 75 % participant satisfaction. A 77.3 % recruitment rate was achieved, with 44 participants enrolled. Participants wore their insoles an average of 7.4 hours per day, and insoles recorded an average of 5.5 hours per day. Peak force, impulse, and loading rate collected at baseline and follow-up were 100 % usable. During the real-world settings, 87.8 % of data was deemed usable with an average of 1200 min/participant. Lastly, average satisfaction was 80.5 %. These results suggest that force-sensing insoles appears to be feasible to capture real-world limb loading in older adults.

Transient pain and discomfort when wearing high-heeled shoes.

In the dynamic world of fashion, high-heeled footwear is revered as a symbol of style, luxury and sophistication. Yet, beneath the facade of elegance of classy footwear lies the harsh reality of discomfort and pain. Thus, this study aims to investigate the influence of wearing high-heeled shoes on the sensation of pain across different body regions over a period of 6 h. It involved fifty female participants, all habitual wearers of high-heeled shoes, aged between 20 and 30 years. Each participant kept a record of their perceptions of pain and discomfort every hour for a total of 6 h using a 0-10 pain scale with 0 indicating no pain and 10 indicating severe pain. The findings reveal a progressive rise in pain throughout wear, with the most intense pain reported in the back, calcaneus, and metatarsals. The analysis shows that after approximately 3.5 h, participants experience significant increases in pain levels. However, the relationship between heel height and pain is not linear. It appears that a heel height of 7.5 cm is the threshold where overall body pain becomes significant. The study suggests that a duration of 3.5 h of wear and a heel height of 7.5 cm serve as critical points to decrease overall body pain. Moreover, beyond this heel height, knee pain diminishes compared to other body areas possibly due to the shift towards a more neutral posture. The study findings, coupled with the recommendations, can assist footwear designers in crafting not only stylish but also comfortable shoes.

Anthropometric and physical fitness indicators in the combine draft between the finalist and the eliminated player in the national basketball association all-star slam dunk contest.

Little is known about the difference of anthropometry and physical fitness between the finalist and eliminated player in the NBA all star slam dunk contest. This study aimed to compare the difference on anthropometric and physical fitness indicator in the combine draft between finalist and eliminated player in the national basketball association all star slam dunk contest. Draft data of 32 basketball players (N = 32, age in draft year: 20.69±2.28 years old, height without shoes: 196.75±8.68 cm, weight: 96.85±10 kg, body fat percentage: 6.07±1.23%) participating in the 2000-2015 draft and 2003-2023 slam dunk contest was selected from national basketball association database. It was classified into finals group (FG) (N = 16) and elimination group (EG) (N = 16). Independent sample t-test with cohen's d was adopted for evaluating the statistical significance of intergroup difference and its effect size. The result indicates that Finalist group was significant less than elimination group on height without shoes (FG vs EG: 193.43±9.47 cm vs 200.06±6.52 cm, P<0.05), standing reach (FG vs EG: 257.66±12.32 cm vs 268.29±10.03 cm, P<0.05) and weight (FG vs EG: 93.38±7.37 kg vs 100.33±11.25 kg, P<0.05). Conversely, compared to elimination group,finalist group has significant better performance on three quarter court sprint (FG vs EG: 3.15±0.1 s vs 3.26±0.12 s, P<0.05), standing vertical jump (FG vs EG: 84.88±5.13 cm vs 78.83±4.9 cm, P<0.05) and max vertical jump (FG vs EG: 102.39±6.47 cm vs 94.79±8.34 cm, P<0.05). However, effect size analysis indicated that height without shoes,standing reach,weight (cohen's d = 0.73-0.959, 0.7≤cohen's d<1.3, moderate) from the anthropometric indicator and three quarter court sprint, standing vertical jump, and max vertical jump (cohen's d = 0.97-1.21, 0.7≤cohen's d<1.3, moderate) from physical fitness indicator has moderate effect size, whereas effect size of body fat percentage, wingspan and lane agility time (cohen's d = 0.31-0.67, 0.3≤cohen's d<0.7, small) was small. To conclude, specific anthropometric and physical fitness indicator shows clear difference between finals group and elimination group. Height without shoes, standing reach,weight in anthropometry and three quarter court sprint, standing vertical jump, and max vertical jump in physical fitness are key indicator to slam dunk performance. In line with the result in the study, NBA staff can select suitable rookies for slam dunk contest. Similiarly, coach from NBA or other basketball league, who want to improve the player's slam dunk performance, should use specific training programs to develop the slam dunk-related indicator.

Stepping into the Right Shoes: The Effects of User-Matched Avatar Ethnicity and Gender on Sense of Embodiment in Virtual Reality.

In many consumer virtual reality (VR) applications, users embody predefined characters that offer minimal customization options, frequently emphasizing storytelling over user choice. We explore whether matching a user's physical characteristics, specifically ethnicity and gender, with their virtual self-avatar affects their sense of embodiment in VR. We conducted a $2\times 2$ within-subjects experiment ($\mathrm{n}=32$) with a diverse user population to explore the impact of matching or not matching a user's self-avatar to their ethnicity and gender on their sense of embodiment. Our results indicate that matching the ethnicity of the user and their self-avatar significantly enhances sense of embodiment regardless of gender, extending across various aspects, including appearance, response, and ownership. We also found that matching gender significantly enhanced ownership, suggesting that this aspect is influenced by matching both ethnicity and gender. Interestingly, we found that matching ethnicity specifically affects self-location while matching gender specifically affects one's body ownership.

Assessment of Sensorized Insoles in Balance and Gait in Individuals With Parkinson's Disease.

Individuals with Parkinson's disease (PD) are characterized by gait and balance disorders limiting their independence and quality of life. Home-based rehabilitation programs, combined with drug therapy, demonstrated to be beneficial in the daily-life activities of PD subjects. Sensorized shoes can extract balance- and gait-related data in home-based scenarios and allow clinicians to monitor subjects' activities. In this study, we verified the capability of a pair of sensorized shoes (including pressure-sensitive insoles and one inertial measurement unit) in assessing ground-level walking and body weight shift exercises. The shoes can potentially be combined with a sensory biofeedback module that provides vibrotactile cues to individuals. Sensorized shoes have been assessed in terms of the capability of detecting relevant gait events (heel strike, flat foot, toe off), estimating spatiotemporal parameters of gait (stance, swing, and double support duration, stride length), estimating gait variables (vertical ground-reaction force, vGRF; coordinate of the center of pressure along the longitudinal axes of the feet, yCoP; and the dorsiflexion angle of the feet, Pitch angle). The assessment compared the outcomes with those extracted from the gold standard equipment, namely force platforms and a motion capture system. Results of this comparison with 9 PD subjects showed an overall median absolute error lower than 0.03 s in detecting the foot-contact, foot-off, and heel-off gait events while performing ground-level walking and lower than 0.15 s in body weight shift exercises. The computation of spatiotemporal parameters of gait showed median errors of 1.62 % of the stance phase duration and 0.002 m of the step length. Regarding the estimation of vGRF, yCoP, and Pitch angle, the median across-subjects Pearson correlation coefficient was 0.90, 0.94, and 0.91, respectively. These results confirm the suitability of the sensorized shoes for quantifying biomechanical features during body weight shift and gait exercises of PD and pave the way to exploit the biofeedback modules of the bidirectional interface in future studies.

Human-in-the-loop optimization of rocker shoes via different cost functions during walking.

Personalised footwear could be used to enhance the function of the foot-ankle complex to a person's maximum. Human-in-the-loop optimization could be used as an effective and efficient way to find a personalised optimal rocker profile (i.e., apex position and angle). The outcome of this process likely depends on the selected optimization objective and its responsiveness to the rocker parameters being tuned. This study aims to explore whether and how human-in-the-loop optimization via different cost functions (i.e., metabolic cost, collision work as measure for external mechanical work, and step distance variability as measure for gait stability) affects the optimal apex position and angle of a rocker profile differently for individuals during walking. Ten healthy individuals walked on a treadmill with experimental rocker shoes in which apex position and angle were optimized using human-in-the-loop optimization using different cost functions. We compared the obtained optimal apex parameters for the different cost functions and how these affected the selected gait related objectives. Optimal apex parameters differed substantially between participants and optimal apex positions differed between cost functions. The responsiveness to changes in apex parameters differed between cost functions. Collision work was the only cost function that resulted in a significant improvement of its performance criteria. Improvements in metabolic cost or step distance variability were not found after optimization. This study showed that cost function selection is important when human-in-the-loop optimization is used to design personalised footwear to allow conversion to an optimum that suits the individual.

Using In-Shoe Inertial Measurement Unit Sensors to Understand Daily-Life Gait Characteristics in Patients With Distal Radius Fractures During 6 Months of Recovery: Cross-Sectional Study.

BACKGROUND: A distal radius fracture (DRF) is a common initial fragility fracture among women in their early postmenopausal period, which is associated with an increased risk of subsequent fractures. Gait assessments are valuable for evaluating fracture risk; inertial measurement units (IMUs) have been widely used to assess gait under free-living conditions. However, little is known about long-term changes in patients with DRF, especially concerning daily-life gait. We hypothesized that, in the long term, the daily-life gait parameters in patients with DRF could enable us to reveal future risk factors for falls and fractures. OBJECTIVE: This study assessed the spatiotemporal characteristics of patients with DRF at 4 weeks and 6 months of recovery. METHODS: We recruited 16 women in their postmenopausal period with DRF as their first fragility fracture (mean age 62.3, SD 7.0 years) and 28 matched healthy controls (mean age 65.6, SD 8.0 years). Daily-life gait assessments and physical assessments, such as hand grip strength (HGS), were performed using an in-shoe IMU sensor. Participants' results were compared with those of the control group, and their recovery was assessed for 6 months after the fracture. RESULTS: In the fracture group, at 4 weeks after DRF, lower foot height in the swing phase (P=.049) and higher variability of stride length (P=.03) were observed, which improved gradually. However, the dorsiflexion angle in the fracture group tended to be lower consistently during 6 months (at 4 weeks: P=.06; during 6 months: P=.07). As for the physical assessments, the fracture group showed lower HGS at all time points (at 4 weeks: P<.001; during 6 months: P=.04), despite significant improvement at 6 months (P<.001). CONCLUSIONS: With an in-shoe IMU sensor, we discovered the recovery of spatiotemporal gait characteristics 6 months after DRF surgery without the participants' awareness. The consistently unchanged dorsiflexion angle in the swing phase and lower HGS could be associated with fracture risk, implying the high clinical importance of appropriate interventions for patients with DRF to prevent future fractures. These results could be applied to a screening tool for evaluating the risk of falls and fractures, which may contribute to constructing a new health care system using wearable devices in the near future.

In-Shoe Pressure Measurements in Diabetic Footwear Practice: Success Rate and Facilitators of and Barriers to Implementation.

We aimed to assess the success rate and facilitators of and the barriers to the implementation of in-shoe plantar pressure measurements in footwear practice for people with diabetes at high risk of foot ulceration. Eleven Dutch footwear practices were partly supported in purchasing a pressure measurement system. Over a 2.5-year period, trained shoe technicians evaluated 1030 people with diabetes (range: 13 to 156 across practices). The implementation success and associated facilitators and barriers were evaluated quantitatively using completed measurement forms and pressure measurement data obtained during four monitoring sessions and qualitatively through semi-structured interviews with technicians. Across the 11 practices, the primary target group (people with diabetes and a healed plantar foot ulcer) represented 25-90% of all the patients measured. The results showed that three practices were successful, five moderately successful, and three not successful. The facilitators included support by the company management board, collaboration with a prescribing physician, measurement sessions separate from the outpatient clinic, and a (dedicated) shoe technician experiencing a learning effect. The barriers included investment costs, usability aspects, and limited awareness among shoe technicians. In-shoe plantar pressure measurements can be implemented to a moderate to large degree in diabetic footwear practice. The barriers to and facilitators of implementation are organizational, logistical, financial, or technical, and the barriers are modifiable, supporting future implementation.

Stepping Forward: A Scoping Systematic Literature Review on the Health Outcomes of Smart Sensor Technologies for Diabetic Foot Ulcers.

Diabetic foot ulcers (DFUs) pose a significant challenge in diabetes care, demanding advanced approaches for effective prevention and management. Smart insoles using sensor technology have emerged as promising tools to address the challenges associated with DFU and neuropathy. By recognizing the pivotal role of smart insoles in successful prevention and healthcare management, this scoping review aims to present a comprehensive overview of the existing evidence regarding DFU studies related to smart insoles, offloading sensors, and actuator technologies. This systematic review identified and critically evaluated 11 key studies exploring both sensor technologies and offloading devices in the context of DFU care through searches in CINAHL, MEDLINE, and ScienceDirect databases. Predominantly, smart insoles, mobile applications, and wearable technologies were frequently utilized for interventions and patient monitoring in diabetic foot care. Patients emphasized the importance of these technologies in facilitating care management. The pivotal role of offloading devices is underscored by the majority of the studies exhibiting increased efficient monitoring, prevention, prognosis, healing rate, and patient adherence. The findings indicate that, overall, smart insoles and digital technologies are perceived as acceptable, feasible, and beneficial in meeting the specific needs of DFU patients. By acknowledging the promising outcomes, the present scoping review suggests smart technologies can potentially redefine DFU management by emphasizing accessibility, efficacy, and patient centricity.

Increased oxidative stress in shoe industry workers with low-level exposure to a mixture of volatile organic compounds.

This study aimed to assess the redox status and trace metal levels in 49 shoe industry workers (11 men and 38 women) occupationally exposed to a mixture of volatile organic compounds (VOCs), which includes aliphatic hydrocarbons, aromatic hydrocarbons, ketones, esters, ethers, and carboxylic acids. All measured VOCs were below the permitted occupational exposure limits. The control group included 50 unexposed participants (25 men and 25 women). The following plasma parameters were analysed: superoxide anion (O2 •-), advanced oxidation protein products (AOPP), total oxidative status (TOS), prooxidant-antioxidant balance (PAB), oxidative stress index (OSI), superoxide dismutase (SOD) and paraoxonase-1 (PON1) enzyme activity, total SH group content (SHG), and total antioxidant status (TAS). Trace metal levels (copper, zinc, iron, magnesium, and manganese) were analysed in whole blood. All oxidative stress and antioxidative defence parameters were higher in the exposed workers than controls, except for PON1 activity. Higher Fe, Mg, and Zn, and lower Cu were observed in the exposed vs control men, while the exposed women had higher Fe and lower Mg, Zn, and Cu than their controls. Our findings confirm that combined exposure to a mixture of VOCs, even at permitted levels, may result in additive or synergistic adverse health effects and related disorders. This raises concern about current risk assessments, which mainly rely on the effects of individual chemicals, and calls for risk assessment approaches that can explain combined exposure to multiple chemicals.

Acute effects of negative heel shoes on perceived pain and knee biomechanical characteristics of runners with patellofemoral pain.

BACKGROUND: To determine the effects of negative heel shoes on perceived pain and knee biomechanical characteristics of runners with patellofemoral pain (PFP) during running. METHODS: Sixteen runners with PFP ran in negative (-11 mm drops) and positive (5 mm drops) heel shoes while visual analog scale (VAS) scores, retroreflective markers, and ground reaction force were acquired by applying a 10-cm VAS, infrared motion capture system, and a three-dimensional force plate. Knee moment, patellofemoral joint stress (PFJS), and other biomechanical parameters during the stance phase were calculated based on inverse dynamics and a biomechanical model of the patellofemoral joint. RESULTS: The foot inclination angle, peak PFJS during the stance phase, patellofemoral joint reaction force, knee extension moment, and quadriceps force at the time of peak PFJS of runners with PFP in negative heel shoes were lower than that in positive heel shoes, no significant difference was found in VAS scores, knee flexion angle, patellofemoral contact area, and quadriceps moment arm at the time of peak PFJS. CONCLUSIONS: Compared to positive heel shoes, running in negative heel shoes decreases peak PFJS in runners with PFP, which may decrease patellofemoral joint loading, thus reducing the possibility of further development of PFP. TRAIL REGISTRATION: Sports Science Experiment Ethics Committee of Beijing Sport University. 2023095H, April 18, 2023 (prospectively registered).

Effects of shoe collar height and limb dominance on landing knee biomechanics in female collegiate volleyball players.

Volleyball-specific footwear with higher collar heights (a mid-cut shoe) are worn to restrict ankle motion. Reduced ankle dorsiflexion has been associated with increased frontal plane motion and injury risk at the knee. With the high frequency of unilateral landings in volleyball, the purpose of this study was to determine the effect of volleyball-specific shoes and limb dominance on knee landing mechanics in collegiate volleyball players. It was hypothesized that participants would exhibit smaller sagittal plane and greater frontal plane knee joint mechanics in mid-cut and dominant limb and that vertical and posterior directed ground reaction forces would be greater wearing mid-cut, yet similar between limbs. Seventeen female volleyball players performed unilateral landings on each limb in mid-cut and low-top volleyball shoes. For shoe main effects, smaller peak dorsiflexion angle and internal peak plantarflexion moment and greater peak medial ground reaction force were found in the mid-cut but with no impact on knee mechanics. For limb main effects, the internal peak knee abduction moment was greater in the dominant limb. Greater peak lateral ground reaction force was found in the interaction between the non-dominant limb and low-top. Further research is warranted to better understand shoe and limb impact in volleyball players.

Offloading and adherence through technological advancements: Modern approaches for better foot care in diabetes.

OBJECTIVE: This manuscript aims to provide a review and synthesis of contemporary advancements in footwear, sensor technology for remote monitoring, and digital health, with a focus on improving offloading and measuring and enhancing adherence to offloading in diabetic foot care. METHODS: A narrative literature review was conducted by sourcing peer-reviewed articles, clinical studies, and technological innovations. This paper includes a review of various strategies, from specifically designed footwear, smart insoles and boots to using digital health interventions, which aim to offload plantar pressure and help prevent and manage wounds more effectively by improving the adherence to such offloading. RESULTS: In-house specially made footwear, sensor technologies remotely measuring pressure and weight-bearing activity, exemplified for example, through applications like smart insoles and SmartBoot, and other digital health technologies, show promise in improving offloading and changing patient behaviour towards improving adherence to offloading and facilitating personalised care. This paper introduces the concept of gamification and emotive visual indicators as novel methods to enhance patient engagement. It further discusses the transformative role of digital health technologies in the modern era. CONCLUSIONS: The integration of technology with footwear and offloading devices offers unparallelled opportunities for improving diabetic foot disease management not only through better offloading but also through improved adherence to offloading. These advancements allow healthcare providers to personalise treatment plans more effectively, thereby promising a major improvement in patient outcomes in diabetic foot ulcer healing and prevention.

Influence of altered torsional stiffness through sole modification of air pressure shoes on lower extremity biomechanical behaviour during side-step cutting maneuvers.

Directional changes in cutting maneuvers are critical in sports, where shoe torsional stiffness (STS) is an important factor. Shoes are designed based on different constructions and movement patterns. Hence, it is unclear how adjustable spacers into the sole constructions of air pressure chambers (APC) affect the STS in side-step cutting. Therefore, this study investigated the effects of altered STS through adjustable sole spacers on ground reaction force (GRF) and ankle and knee joint moments in side-step cutting. Seventeen healthy recreational athletes performed side-step cutting with experimental conditions including (i) barefoot (BF), (ii) unaltered shoes (UAS): soles consisting of APC, and (iii) altered shoes (AS): modified UAS by inserting elastomeric spacers into cavities formed by APC. Mechanical and biomechanical variables were measured. Significant differences were revealed across shoe conditions for impact peak (p = 0.009) and impulse (p = 0.018) in vertical GRF, time to achieve peak braking (p = 0.004), and peak propulsion (p = 0.025) for anterior-posterior GRF in ANOVA test. No significant differences were observed in GRF peaks and impulses between UAS and AS except for a trend of differences in impact peak (p = 0.087) for vertical GRF. At the ankle and knee joint, peak ankle power absorption (p = 0.019), peak knee internal rotation moment (p = 0.042), peak knee extension moment (p = 0.001), peak knee flexion moment (0.000), peak knee power absorption (p = 0.047) showed significant difference across three shoe conditions. However, no significant differences between the UAS and AS were noticed for peak joint moments and power. Altered shoe torsional stiffness did not significantly affect the peak forces and peak ankle and knee joint moments or powers; hence sole adjustment did not influence the cutting performance. This study might be insightful in sports footwear design, and adjusting shoe torsional stiffness by sole modification might be advantageous for athletes playing sports with cutting maneuvers to reduce the risk of injuries by controlling the twisting force at the ankle that frequently happens during cutting maneuvers.

Effect of midsole hardness and surface type cushioning on landing impact in heel-strike runners.

High loading impact associated with heel strikes causes running injuries. This study aimed to investigate how loading impact is affected by midsole hardness and running surface type. Twelve young rear-foot runners ran at a fixed speed along an 18 m runway wearing shoes with different midsole hardness (Asker C-45, C-50, C-55, C-60, from soft to hard) and on two different surfaces (rubber and concrete). We quantified vertical average loading rate (VALR) and vertical impact peak force (VIPF). We conducted midsole × surface repeated-measures ANOVA on loading impact measures, and one-sample t-tests to compare VALR with a threshold value (80 BW·s-1). Midsole hardness and surface type mainly affected VALR. Although no significant effect of these variables was observed for VIPF magnitude, there were effects on time to VIPF and steps with VIPF. Several combinations of midsole and surface hardness reduced VALR below 80 BW·s-1: Asker C-45 with both surfaces, and Asker C-50 with a rubber surface. The combination of softer midsole and surface effectively reduced loading rates as shown by increased time to VIPF and reduced VALR. Combining softer midsole and surface results in the greatest cushioning, which demonstrates the benefit of considering both factors in reducing running injuries.