Search Results (217)

Background/Objectives: Running is associated with increased Achilles Tendon (AT) loading and cross-sectional area (CSA). Achilles tendinopathy is a common unilateral injury. Differences in AT loading variables between dominant and non-dominant lower extremities while running have not been characterized. This study examined the AT loading variables between dominant and non-dominant lower extremities in healthy recreational runners. Methods: Twenty-four females ran at 3.3 m/s (11.88 km/hr) on an instrumented treadmill. Achilles Tendon CSA (AT-CSA) was measured from ultrasound images. Kinematic and kinetic data were used as input into a musculoskeletal model. Paired t-tests examined inter-limb differences in peak vertical ground reaction force, Achilles Tendon-related loading variables (AT force, AT-CSA, AT stress), total gastrocnemius force, soleus force, foot strike angle, and stance time. Results: No differences were shown between dominant and non-dominant lower extremities in stance time, vertical ground reaction force, gastrocnemius and soleus force, AT force, AT-CSA, or AT stress. Foot strike angle was different between limbs (p = 0.015); however, the absolute difference was about 2°. Conclusions: These data indicated that AT loading was similar between dominant and non-dominant lower extremities in healthy female recreational runners. While some asymmetry can be expected during a bilateral task such as running, runners displayed differences in AT force and stress less than 18%. These data may assist clinicians in the assessment and management of runners recovering from AT tendinopathy. Full article

A triathlon is a multi-sport event that consists of three simultaneous events: swimming, biking, and running. This sport has experienced significant growth in the past few decades, with colleges and universities now participating. This exploratory mixed-methods study examined the motivations and perceived health benefits of college triathletes during the COVID-19 pandemic, using the Means-Ends of Recreation Scale and the Perceived Health Outcomes of Recreation Scale (N = 29), as well as semi-structured interviews (N = 4). Results indicate no difference in motives or health outcomes between male and female survey respondents. The thematic analysis of open-ended interview questions highlighted lived experiences. The results obtained provide preliminary evidence of the importance of motivation and health outcomes of college triathletes during the pandemic. Full article

Background: Video-based biomechanical running gait analysis is widely used to optimise technique, guide footwear selection, and identify orthopaedic risk factors. Despite the increasing availability of such assessments, it is often assumed—without strong empirical support—that key kinematic parameters of running gait remain stable over short periods of time. This study aimed to examine the short-term stability of key joint angles during running using a standard 2D video-based kinematic analysis. Specifically, it was investigated whether these angles change within the first 4 min of treadmill running under three defined conditions: barefoot at 12 km h⁻¹, shoed at 12 km h⁻¹, and shoed at 14 km h⁻¹, in a homogeneous sample of twelve young, trained, male recreational soccer players. Methods: Participants completed three four-minute runs. Joint angles were quantified manually from 2D video recordings. Temporal variation was analysed using repeated-measures statistics, intraclass correlation coefficients (ICCs), and minimal detectable changes (MDCs). Results: Six out of nine joint angles showed statistically significant temporal changes, mainly in hip extension, knee flexion, the Duchenne angle, the Trendelenburg angle, the leg axis angle, and heel-bottom angle. Lower leg angle and Achilles tendon angle remained stable. ICCs showed moderate to excellent agreement, indicating high within-session consistency across all angles. Discussion: Under the applied study protocol, significant short-term variations were observable in several joint angles during the first four minutes of running. These findings highlight the importance of analysing multiple strides and considering measurement uncertainty when interpreting short-duration running kinematics. Full article

Background: Street running has seen rapid growth due to its health benefits and accessibility, leading to a simultaneous rise in running-related injuries, particularly among recreational and professional street runners. Medial Tibial Stress Syndrome (MTSS) is a common injury affecting up to 15% of athletes and posing significant risks to runners of all levels of participation. Objective: This study aimed to investigate the strength and kinematic differences in the lower limbs of runners diagnosed with MTSS compared to asymptomatic runners. Methods: A total of 56 participants were divided into an MTSS group (27 runners) and a healthy control group (29 runners). Participants were evaluated for demographics, physical activity level, pain threshold using algometry, and running kinematics obtained through high-resolution 2D video analysis with Kinovea software. Lower-limb muscle strength was measured using an isometric Lafayette^® digital dynamometer. Results: Although there were no significant differences in age or anthropometric measures, MTSS runners exhibited lower initial (∆% = 10.6%, p = 0.002) and intermediate (∆% = 8.7%, p = 0.026) running speeds. Pain assessment revealed significant lower pain thresholds in the MTSS group. Kinematic analysis identified greater foot-strike angles (left foot: ∆% = 31.9%, p = 0.004; right foot: ∆% = 25.9%, p = 0.0049) at initial speeds in MTSS runners, while other parameters like medial calcaneus rotation, push-off angles, and support time did not differ significantly. Additionally, MTSS runners demonstrated reduced strength in the quadriceps femoris (QF—Left QF: ∆% = −28.5%, p = 0.0049; Right QF: ∆% = −28.2%, p = 0.003). Conclusions: MTSS appears to affect female and male runners. MTSS may be attributed to a weaker quadriceps strength, higher heel contact angles during foot strike, or both, suggesting that interventions focusing on the improvement of these factors may be beneficial in preventing and treating MTSS. Full article

(1) Background: The midsole hardness (i.e., cushioning) of running shoes has received significant attention as a crucial element influencing both performance and injury prevention. This research aimed to examine how variations in midsole hardness affect the biomechanical responses of the lower extremities during running. (2) Methods: Twenty-five male recreational runners in their 20 s with no history of musculoskeletal injuries (age: 23.3 ± 4.24 years) were recruited. Custom-made shoes with four different midsole hardness levels (Asker-C 70, 60, 50, and 40) were used, and the mechanical properties of the midsoles were analyzed. Participants ran on an instrumented treadmill at speeds of 2.3 m/s and 3.3 m/s. Ground reaction forces and motion data were collected during the trials. A one-way repeated-measures ANOVA was conducted to compare groups. (3) Results: In the running trials, a decrease in midsole hardness increased the impact peak (IP) while loading rate (LR) decreased significantly (p < 0.05). In addition, runners wearing shoes with greater cushioning exhibited higher ankle joint stiffness than those wearing harder shoes (p < 0.05). (4) Conclusions: Adjusting joint stiffness appears to be a key strategy employed by runners in response to softer or cushioned running environments (i.e., shoe and surface), ultimately contributing to greater dynamic stability during movement. Full article

Background: Ultramarathon running represents an extreme physiological and metabolic challenge. Despite its growing popularity among recreational and competitive runners, evidence-based guidance for nutrition, energy balance, and recovery remains limited. Understanding metabolic response and hormonal regulation during such events is crucial for improving athletes’ health and performance. Methods: This prospective observational study examined participants of the 2024 TorTour de Ruhr^® (100 km, 160.9 km, and 230 km). Pre- and post-race assessments included body composition, energy intake and expenditure, metabolic and hormonal biomarkers (leptin, ghrelin, insulin, glucagon, irisin, creatine kinase muscle type (CKM), lactate dehydrogenase (LDH)), and continuous glucose monitoring (CGM). Blood and saliva samples, bioimpedance analysis, and validated symptom questionnaires (General Assessment of Side Effects (GASE)) were used. Results: Of the 43 ultra runners (16 women, 27 men), 39 finished the race: 19 participants of the 100 km group, 8 of the 160.9 km group, and 16 of the 230 km group. Mean energy deficit was 6797 kcal (range: 417–18,364 kcal) with carbohydrate-dominant fueling (79%). Significant reductions in leptin and insulin and increases in ghrelin, glucagon, CKM, and LDH were observed, indicating disrupted energy homeostasis and muscle damage. The 230 km subgroup showed the greatest changes. Gastrointestinal and musculoskeletal symptoms increased post-race, aligning with biomarker patterns. Conclusions: Ultramarathon participation induces profound disturbances in metabolic and structural integrity, regardless of race distance. These findings underline the importance of developing individualized nutritional and recovery strategies and highlight the need for future research to investigate how energy deficit and macronutrient composition interact to influence metabolic strain and post-race recovery. Full article

Aims: Structural lower limb-length discrepancies (LLLD) have been classically associated with the etiology of low back pain. However, their biomechanical effects on lower-limb muscle activity during running remain unclear. This pilot crossover study aimed to evaluate the influence of orthotic interventions—designed to compensate for LLLD and modify foot biomechanics—on the electromyographic (EMG) activity of the contralateral tensor fasciae latae (TFL) in healthy runners. Methods: A total of 41 recreational male and female runners (mean age 32.27 ± 6.09) with structural LLLD were recruited and classified as neutral (Ng), supinated (SPg), or pronated (PRg) based on their foot posture. Surface EMG activity of the TFL in the longer leg was recorded with specific surface electrodes while participants ran on a treadmill at a constant speed of 9 km/h for 3 min. Each subject randomly wore standard orthoses with 5 mm pronating (PRO), supinating (SUP) wedges or orthoses with a heel lift (TAL) to compensate for the shorter leg, alongside the baseline condition (SIN). Results: Perfect reliability (close to 1) was obtained for all measurements. A statistically significant reduction in TFL EMG activity was recorded in the Ng group: SIN 105.64 ± 50.6%MVC vs. PRO 100.16 ± 48.61%MVC (p < 0.05), and SIN vs. TAL 93.49 ± 15.88%MVC (p < 0.001). A significant reduction was also observed in the PRg group: SIN 91.82 ± 40.75%MVC vs. TAL 80.08 ± 31.75%MVC (p < 0.05). Conclusion: Orthotic compensation for LLLD and foot pronation modifications produced measurable changes in TFL EMG activity during running. These findings provide mechanistic insight into the interaction between limb-length asymmetry, foot biomechanics, and proximal muscle activation in runners, and may inform future studies on overuse injuries such as iliotibial band syndrome. Full article

Although the hamstring muscles play an important role in running, very little is known about the individual contributions of each hamstring muscle (biceps femoris_{long head}, biceps femoris_{short head}, semitendinosus, and semimembranosus) toward running economy. As such, our study examined all the muscles in the hamstring to provide insight into which muscles contribute the most to running economy. Such information can provide insight in designing precise exercise training programs for enhancing running performance. Secondary analysis from our cross-sectional study conducted on 23 male recreational runners examined the relationships between stretch shortening cycle potentiation (via leg press throw), running net VO₂ (inverse of running economy) (at 11.3 km/h), and maximum cross-sectional area of biceps femoris_{long head}, biceps femoris_{short head}, semitendinosus, and semimembranosus was assessed via magnetic resonance imaging. We obtained significant correlations between the maximum cross-sectional area of the biceps femoris_{long head} and log₁₀running net VO₂ (r = −0.52; p < 0.05). Our multiple regression model showed that the maximum cross-sectional area of biceps femoris_{long head} but not stretch shortening cycle potentiation predicted log₁₀running net VO₂ (r = −0.52; p < 0.01). We found no other relationship between any other hamstring muscles and log₁₀running net VO₂. Our findings provide preliminary evidence of the importance of the biceps femoris_{long head} toward running economy. This may be due to the preferential activation of efficient slow twitch muscle fibers of the biceps femoris_{long head}. Additionally, we noted that the biceps femoris_{short head}, semitendinosus, and semimembranosus muscles were not related to running economy in recreational male runners. Full article

Background/Objectives: Ingestion of galactooligosaccharides (GOSs) or GOS mixtures has been purported to improve exercise-induced gastrointestinal (GI) distress and post-exercise recovery. However, the effects have not been explored in recreationally trained endurance athletes. This triple-blind randomised controlled trial, therefore, investigated whether 12 weeks of B-GOS^® supplementation affects gastrointestinal comfort and psychological wellbeing in recreational athletes. Methods: Eighteen physically active individuals (12 males, 8 females, 44 ± 14 years, 1.7 ± 0.1 m and 73 ± 14 kg) volunteered for this study. Participants were assigned to independent groups in a placebo-controlled, triple-blind manner via stratified randomisation. A 20 min run at 80% VO_2max was completed, with measures for GI distress and Competitive State Anxiety Inventory-2 questionnaire (CSAI-2) pre- and post-exercise. A 12-week supplementation period then ensued, where participants ingested either 3.65 g of B-GOS or an appearance-matched maltodextrin placebo. During this time, physical activity levels (IPAQ-7), general stress (REST-Q), mental wellbeing (WEMWBS), and sleep (core consensus sleep diary) were measured at regular time points. Results: There were no significant differences in VO_2max (p = 0.437), GI discomfort (p = 0.227), or CSAI-2 (p = 0.739–0.954) from pre- to post-exercise at any time point or between conditions. Over the 12 weeks there were no significant differences between B-GOS and placebo in IPAQ-7 (p = 0.144–0.723), REST-Q (p = 0.282–0.954), WEMWBS (B-GOS pre = 51 ± 10, post = 53 ± 7; PLA pre = 51 ± 4, post 54; p = 0.862), or sleep (p = 0.065–0.992). The linear mixed model suggests that some may benefit on an individual level in terms of WEMWBS, general stress score, recovery-related scores, sleep, and sport-specific recovery score. Conclusions: There were no group benefits of B-GOS supplementation compared with placebo, although the individual variation may warrant further research in larger sample sizes and longer-duration studies. Full article

Adherence to antiretroviral therapy (ART) is critical for HIV management and sustained virological suppression. Differentiating intentional from unintentional nonadherence is essential for developing tailored interventions, yet evidence from Asian populations remains limited. A cross-sectional study of 846 people with HIV (PWH) in northern Taiwan assessed ART adherence using the MARS-5 scale. Participants were categorized into good, unintentional, or intentional non-adherence groups. Logistic regression identified associated behavioral and psychosocial factors. Recreational drug use and younger age were independently linked to both unintentional and intentional poor adherence. Higher income and the use of single-tablet regimens were protective against intentional nonadherence, whereas disclosure of HIV status to a partner and an unsuppressed viral load were significantly associated with intentional nonadherence. Reported reasons included being too busy, emotional distress, and running out of medication. These findings suggest that intentional and unintentional nonadherence represent distinct behavioral patterns, with intentional lapses more strongly linked to virological failure. Addressing substance use, simplifying regimens, and providing psychosocial support after disclosure are essential to optimize adherence and achieve UNAIDS 2030 targets. Full article

Running is one of the most popular recreational sports worldwide, yet it carries a high risk of sports injuries. While various risk factors have been identified, sleep has emerged as a potentially important but understudied contributor in recreational running. This study investigates whether distinct sleep profiles can predict sports injuries in recreational runners. A secondary analysis was conducted on survey data from 425 Dutch recreational runners. Latent profile analysis was applied to identify sleep risk profiles based on sleep duration, sleep quality, and sleep problems. Binary logistic regression tested the association between sleep profile membership and self-reported sports injuries, controlling for demographic and training variables. Findings revealed that four sleep profiles could be identified: Steady Sleepers, Poor Sleepers, Efficient Sleepers, and Fragmented Sleepers. Runners classified as Poor Sleepers were significantly more likely to report sports injuries than Steady Sleepers (OR = 1.78, 95% CI = 1.14–2.78; p = 0.01), with 68% injury probability. No significant differences were found for the other profiles. These findings underscore the importance of sleep as a multidimensional factor in injury prevention in recreational running, and suggest that interventions focusing on sleep duration and sleep quality may benefit running athletes’ health. Full article

Background: Previous research has identified center of mass vertical oscillation and leg stiffness as the most common variables differentiating Natural and Groucho running techniques. The aim was to assess the inter-session reliability and inter-technique sensitivity of synchronized inertial measurement units and contact grids in quantifying kinematic and kinetic differences between Natural and Groucho running techniques. Methods: Eleven physically active and healthy males ran at a speed 50% higher than transition speed. Two sessions for Natural and two for Groucho running were performed, each lasting 1 min. Results: Most variables exhibited a similar inter-session reliability across running techniques, except contact time and center of mass vertical displacement, ranging from moderate to good (ICC = 0.538–0.897). A statistically significant difference between running techniques was found for all variables (p < 0.05), except for contact time and center of mass vertical oscillation (p > 0.05), likely due to inconsistency in reliability depending on the running technique, which may have covered the underlying differences. Conclusions: We can conclude that the combination of synchronized inertial measurement units and contact grids showed potentially acceptable reliability and sufficient sensitivity to recognize and differentiate between Natural and Groucho running techniques. The results may contribute to a broader understanding of the differences between these two running techniques and encourage the increased use of these devices within therapeutic, recreational, and sports running contexts. Full article

Background: Recreational running is a globally popular activity known for its physical and mental health benefits, including stress reduction and improved quality of life. However, many recreational runners lack structured guidance, increasing their risk of lower limb injuries, often linked to variations in foot posture. Although African populations are well known for their endurance running abilities, limited research has examined their foot biomechanics and injury risk. This study addresses this gap by investigating foot posture and structure among African male recreational runners in South Africa. Methods: A cross-sectional, quantitative design was employed. Data were collected using structured data collection sheets, capturing demographic information, Foot Posture Index (FPI) scores, and Three-Dimensional (3D) foot scans. FPI provided a clinical evaluation of foot posture, while 3D foot scans delivered precise structural measurements. The aim was to describe and compare the foot posture characteristics and bilateral load distribution patterns in this population, using the Foot Posture Index (FPI) and 3D foot scanning as complementary assessment tools. Results: Findings showed agreement between FPI and 3D foot scan results, with both tools identifying a high prevalence of flexible flat feet among participants. Each method captured unique aspects of foot posture: FPI offered a qualitative overview, while 3D scans provided detailed, quantitative insights. This dual-assessment approach supports the value of using complementary methods in clinical and sports settings. Conclusions: This study suggests that integrating FPI and 3D scanning enhances the accuracy of foot posture assessments. Despite limitations such as a moderate sample size, the findings support personalized clinical interventions and footwear design tailored to the unique biomechanics of Black African male runners. Full article

Background: Physical activity induces the production of reactive oxygen species (ROS), which, at moderate levels mediate beneficial physiological adaptations, including insulin sensitivity and enhanced antioxidant defense. However, excessive ROS production during intense exercise may exceed endogenous antioxidant capacity, leading to oxidative stress and muscle damage. Objective: This study examined the effects of 30-day high-dose omega-3 fatty acid supplementation (9 g/day) on plasma fatty acid composition and the activity of antioxidant enzymes in recreational (n = 11) and trained (n = 10) runners, with emphasis on group- and time-specific responses. Methods: Plasma levels of arachidonic acid (AA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) were assessed at three time points: pre-, during, and post-supplementation period. Enzymatic activities of glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase (CAT) were measured at six time points, including before and after exercise sessions involving a 2800 m run followed by a 400 m sprint. Results: Omega-3 supplementation increased plasma EPA and DHA. In trained runners, it was associated with a transient reduction in GPx and a pronounced mid-phase decline in SOD, whereas enzyme activities remained stable in recreational runners. CAT activity did not change significantly in either group. Conclusions: Short-term high-dose omega-3 supplementation modulates antioxidant enzyme activity in a group- and time-dependent manner. The observed downregulation of GPx and SOD in trained runners may reflect altered redox signaling; however, its relevance for exercise performance remains uncertain. Further studies are warranted to elucidate the physiological and functional consequences of these findings. Full article

Exercise and bone health are crucial for overall cardiovascular and metabolic well-being. However, certain types of activities can increase the risk of osteoporotic fractures. Preventing injuries while remaining active can be challenging, particularly for older competitive recreational athletes whose training volumes can be comparable to those of professional athletes. While high levels of physical activity in older adults typically lead to thicker cortical bone and improved physical fitness, age-related bone loss, hormonal changes, nutrition, and a history of fractures can significantly raise the risk of osteoporosis. This narrative review provides a descriptive summary of the current understanding of the paradox between exercise and bone fragility, particularly in recreational athletes. Many older athletes may be unaware of their declining bone mineral density, believing that their activity levels are sufficient. Ironically, high-impact activities like running and jumping, which are generally recommended for the prevention of osteoporosis, can also increase the risk of stress fractures. Early detection of osteoporosis is crucial, and this can be achieved through DEXA scans and regular bone density tests, allowing for timely intervention before fractures occur. Alongside medications, strength training, as well as balance and stability exercises, can be very beneficial. It is also important to maintain healthy lifestyle choices, ensure adequate energy levels, and consume sufficient amounts of calcium and vitamin D. Furthermore, monitoring training volume and allowing for proper recovery can help reduce the risk of osteoporotic stress fractures in athletes. Full article