Search Results (149)

This study investigated the effects of 6 weeks of plyometric training (PT) performed on soft (unstable) and hard (stable) surfaces compared with conventional training on the balance, explosive power, and muscle strength of adolescent female basketball players. The participants were randomly assigned to three groups: soft-surface PT (n = 14), hard-surface PT (n = 14), and conventional training (n = 14). Performance outcomes included 30 m sprint time, vertical jump height, plantar flexion and dorsiflexion maximal voluntary isometric contraction (MVIC) torque, Y-balance dynamic balance, and center of pressure-based static balance. Ground reaction forces, MVIC torques, and balance parameters were measured using high-precision force sensors to ensure accurate quantification of biomechanical performance. Statistical analyses were performed using two-way repeated-measures ANOVA with post hoc comparisons to evaluate group × time interaction effects across all outcome variables. Results demonstrated that soft- and hard-surface PT significantly improved sprint performance, vertical jump height, and plantar flexion MVIC torque compared with conventional training, while dorsiflexion MVIC increased similarly across all the groups. Notably, soft-surface training elicited greater enhancements in vertical jump height, dynamic balance (posteromedial and posterolateral directions), and static balance under single- and double-leg eyes-closed conditions. The findings suggest that PT on an unstable surface provides unique advantages in optimizing neuromuscular control and postural stability beyond those achieved with stable-surface or conventional training. Thus, soft-surface PT may serve as an effective adjunct to traditional conditioning programs, enhancing sport-specific explosive power and balance. These results provide practical guidance for designing evidence-based and individualized training interventions to improve performance and reduce injury risk among adolescent female basketball athletes. Full article

Muscular strength plays a crucial role in sports performance and is often evaluated using vertical jump tests such as the Squat Jump (SJ) and Countermovement Jump (CMJ). Measurements based on flight time (FT) assume that takeoff and landing postures are identical, yet differences in ankle position can introduce systematic errors. This study examined whether dorsiflexion (DF) or plantarflexion (PF) of the ankle during the flight phase affects jump height. Forty-three active university students completed four repetitions each of SJ and CMJ under DF and PF across two sessions. Jump heights were recorded using a Chronojump-Boscosystem platform. No significant difference was observed in SJ between DF and PF, while CMJ heights were consistently higher under DF (DF: 28.29 cm ± 7.7 cm vs. PF: 27.08 cm ± 7.03 cm, p = 0.001; d = 0.16). Notably, the effect of DF appeared more pronounced in CMJ, suggesting that higher jumps are more sensitive to postural variations. These findings could suggest that DF can artificially increase jump heights as measured on a jump platform, without reflecting true improvements in force production. Coaches and practitioners should interpret FT-derived data with caution, particularly for higher jumps. Future research combining precise motion capture with force platforms could directly track center-of-mass changes and validate this mechanism. Full article

Background/Objectives: Limited ankle dorsiflexion has been associated with compensatory movement patterns throughout the lower extremity kinematic chain. This study investigated relationships between weight-bearing dorsiflexion capacity and lower limb kinematics and plantar pressure patterns during gait. Methods: Twenty-seven healthy adults (age: 22.8 ± 3.4 years) performed a weight-bearing lunge test (WBLT) and walked at a standardized pace across a pressure-sensing walkway while wearing inertial measurement units. Statistical Parametric Mapping assessed correlations between WBLT dorsiflexion and kinematic variables throughout the stance phase. Partial correlations controlled for walking velocity and were used to examine relationships with discrete plantar pressure measurements. Results: Reduced dorsiflexion capacity during the WBLT showed bilateral moderate associations with less ankle dorsiflexion (LEFT: peak r = 0.53; RIGHT: peak r = 0.60) and knee flexion (LEFT: peak r = 0.56; RIGHT: peak r = 0.58) during terminal stance and push-off. Proximal compensations demonstrated limb-specific patterns. Hip abduction was strongly negatively correlated in the left leg only (peak r = −0.65), while pelvic tilt showed bilateral relationships with opposing temporal patterns (LEFT: peak r = −0.58 early stance; RIGHT: peak r = 0.62 terminal stance). Plantar pressure analysis revealed that reduced dorsiflexion was associated with decreased heel relative impulse bilaterally (r = 0.53–0.56) and altered temporal patterns of midfoot loading on the left leg (r = 0.56). Conclusions: Limited dorsiflexion under load is associated with compensatory movement patterns extending from the ankle to the pelvis bilaterally. The evaluation of loaded ankle mobility should be considered an essential component of lower extremity movement assessment. Full article

This study aimed to assess the effect of a downhill-running (DR) bout on muscle damage biomarkers. It also examined whether training background and gait kinematics may influence DR-induced muscle damage and strength loss. Thirty-six experienced trail runners (25 men, 11 women), participants of a 106 km ultra-trail, performed a 5 km DR bout at 15% decline and at an intensity equivalent to their first ventilatory threshold. Muscle damage biomarkers (creatine kinase, lactate dehydrogenase, and myoglobin) were analyzed before and 30 min after the DR protocol, and also before and after the UT race. Isometric strength was assessed before and after DR, and gait parameters were recorded during DR. All muscle damage biomarkers increased following DR (d = 0.19 to 1.85). Lactate dehydrogenase concentrations after the race and DR were associated (r = 0.64). Athletes who habitually performed downhill repetitions showed reduced creatine kinase (182 ± 73 U/L vs. 290 ± 192 U/L; p < 0.05; d = 0.64) and greater squat strength retention (4 ± 10% vs. −9.1 ± 16.8%; p <0.05; d = 0.87). Ankle plantar flexion and squat strength retention were inversely correlated with vertical oscillation (r = −0.44) and step length (r = −0.37), respectively. In summary, lactate dehydrogenase response to a short DR bout could indicate an athlete’s readiness to handle ultra-trail-induced muscle damage, although further research is needed to confirm it. In addition, despite the exploratory nature of the study, regularly performing downhill intervals and adopting a more terrestrial gait pattern appear to soften strength loss and muscle damage response to DR. Full article

Background: The back kick is a key scoring technique in taekwondo, often exhibiting bilateral asymmetry in lower limb function. Understanding these differences is crucial for optimizing training and minimizing injury risk. Methods: This study recruited twelve elite taekwondo athletes to perform back kicks using both their dominant and non-dominant legs under standardized conditions. Kinematic, kinetic, and surface electromyographic data were synchronously collected using a 3D motion capture system, force plate, and sEMG sensors. Paired t-tests and effect sizes assessed bilateral differences. Results: During the leg-lifting phase (P1), attacking leg peak hip power was significantly greater on the non-dominant side (p < 0.01); knee flexion angle was greater on the dominant side (p < 0.01), yet peak knee power was higher on the non-dominant side (p < 0.01). Support leg knee flexion angle was greater on the dominant side (p < 0.01), while knee flexion torque was higher on the non-dominant side (p < 0.05); ankle extension moment (p < 0.05) and plantar flexion power (p < 0.01) favored the dominant side. In the kicking phase (P2), dominant knee power was significantly higher (p < 0.01). The biceps femoris on the non-dominant side showed significantly higher iEMG and RMS values (p < 0.05), and dominant striking speed was faster (p < 0.05). Conclusions: These findings confirm marked functional asymmetry, suggesting training should emphasize non-dominant leg development to improve performance and reduce injury risk. Full article

Background/Objectives: This study aimed to provide preliminary normative data on intersegmental coordination patterns during heel rises at different knee joint positions and across various phases and periods. Methods: Twelve 21-year-old university students from the same cohort performed heel rises in knee-extended and knee-flexed conditions. Shank and foot kinematics were recorded using the VICON Oxford Foot Model, and intersegmental coordination was analyzed using a modified vector coding technique. Results: The results showed that coordination patterns varied significantly between the ascending and descending phases and across the early, middle, and late periods. In the early ascending phase, knee extension exhibited in-phase coordination (shank external rotation with hindfoot inversion), resembling propulsion-related coordination in gait, whereas knee flexion displayed greater anti-phase coordination between hindfoot plantar flexion and forefoot dorsiflexion. The middle and late periods demonstrated heel-rise-specific patterns, with coordination shifting from proximal to distal dominance. Knee flexion altered the coordination between the shank and hindfoot and between the hindfoot and forefoot in the sagittal plane compared to that during knee extension. Conclusions: These findings suggest that the knee position influences intersegmental coordination during heel rises, and the present results provide reference values that can enable future diagnostic validation and comparative studies in pathological populations. Full article

Background/Objectives: Parkinson’s disease (PD) is a progressive neurodegenerative disorder characterized by motor symptoms such as tremor, bradykinesia, rigidity, and postural instability. In the absence of disease-modifying therapies, exercise remains one of the few interventions shown to effectively reduce fall risk and improve mobility. However, it remains unclear whether skeletal muscle ATP metabolism is impaired in PD, and whether the benefits of exercise arise primarily from improvements in central motor control or peripheral metabolic adaptations. Methods: Fourteen individuals with PD and five healthy controls underwent kinetic ³¹P Magnetic Resonance Spectroscopy (MRS) to assess resting muscle ATP synthesis and dynamic ³¹P MRS during in-magnet exercise to evaluate oxidative phosphorylation in active muscle. Results: At rest, ATP synthesis rates mediated by ATPase and creatine kinase (CK) were on average 46 ± 23% and 24 ± 9% lower, respectively, in the PD group compared to controls (p < 0.005), suggesting peripheral mitochondrial dysfunction. During plantar flexion exercise at 15% of lean body mass, range of motion (ROM) was reduced by 22 ± 5% in PD participants (p = 0.01). Despite this, post-exercise recovery of phosphocreatine (PCr) and inorganic phosphate (Pi) was similar between groups. Recovery time constants for PCr and Pi correlated with participants’ total weekly exercise time, indicating a metabolic adaptation to regular physical activity. Modest ROM improvements were observed in both groups following calf-raise exercise training. Conclusions: Reduced skeletal muscle ATP metabolism may contribute to peripheral weakness in PD. Regular exercise appears to promote adaptive metabolic responses, highlighting the need for therapeutic strategies targeting both central and peripheral components of PD. Full article

Background: Reduction in intrinsic foot muscle strength may impair physical performance and increase the risk of falls. Aim: The aim of this study is to analyze the relationship between hallux flexion strength, assessed through the PGT, for physical performance and fall risk in Chilean older adults. Methods: A cross-sectional, descriptive–correlational study was conducted with 188 community-dwelling older adults (89.3% women). Participants’ sociodemographic and anthropometric information was also collected. Hallux plantar flexion strength was assessed using the Paper Grip Test (PGT). Physical performance was evaluated with the Short Physical Performance Battery (SPPB), and fall risk was assessed using the Timed Up and Go (TUG) and Single-Leg Stance Test (SLS). Pearson’s correlation coefficients were calculated for the overall sample, as well as separately for sex. Results: Significant positive correlations were observed between PGT and the total SPPB score for both the right foot (r = 0.178; p = 0.008) and the left foot (r = 0.175; p = 0.009). Additionally, moderate correlations were found between PGT and SLS time (right r = 0.316; p < 0.001; left r = 0.397; p < 0.001), and an inverse correlation was observed between PGT and TUG execution time (right r = −0.372; p < 0.001; left r = −0.393; p < 0.001). Regression models showed that TUG and SLS significantly predicted PGT performance, explaining 17% (R² = 0.17) and 20% (R² = 0.20) of the variance for the right and left foot, respectively. Conclusions: Hallux plantar flexion strength is significantly associated with physical performance and fall risk. The simplicity, low cost, and clinical utility of the PGT support its use as a screening tool for early detection of functional decline. Full article

Introduction: Recurrent ankle sprains can lead to chronic ankle instability. The flossing technique aims to modify the function and characteristics of fascial tissue. The objective was to evaluate the effectiveness of flossing and sliding techniques in improving subjects with previous ankle sprains. Methods: Randomized, double-blind clinical study with a follow-up period. Twenty-six subjects were assigned to two study groups: experimental (flossing technique and passive manual therapy techniques) and placebo control group (flossing technique without compression and manual therapy techniques without sliding). The intervention lasted three weeks, with two sessions per week. The study variables were dorsiflexion under load (Leg Motion^®), ankle mobility under unloaded conditions (goniometer), pressure pain threshold (algometer), and stability (Rs Scan^® pressure platform). Three measurements were taken: pre-treatment (T0), post-treatment (T1), and after 3 weeks of follow-up (T2). Results: There were significant intergroup differences in dorsiflexion under load (F = 4.90; p = 0.02). Range of motion in plantar flexion without load (F = 3.78; p = 0.04), in the ellipse area (F = 4.72; p = 0.01), left stability (F = 3.74; p = 0.03), and right stability (F = 3.73; p = 0.03) without visual support. Conclusions: A physiotherapy protocol using flossing and manual sliding therapy can increase loaded dorsal flexion in young adults with previous ankle sprains. This intervention can also improve ankle plantar flexion under unloaded conditions. The area of the ellipse without visual support can improve in young adults with a history of ankle sprains following a program of flossing and manual therapy. Full article

The ageing of the global population, especially in developed countries, is driving significant societal changes. In Portugal, demographic data reflect a marked increase in the ageing index. Understanding gait alterations associated with ageing is essential for the early detection of mobility decline and fall risk. This study aimed to analyse gait patterns in older adults to contribute to a biomechanical ageing profile. Thirty-six community-dwelling older adults (29 female, 7 male; mean age: 74 years) participated. Gait data were collected using the Xsens full-body motion capture system, which combines inertial sensors with biomechanical modelling and sensor fusion. Spatiotemporal and kinematic parameters were analysed using descriptive statistics. Compared to younger adult norms, participants showed increased stance and double support phases, reduced swing phase, and lower gait speed, stride length, and cadence, with greater step width. Kinematic data showed reduced peak plantar flexion, knee flexion, and hip extension, but increased dorsiflexion peaks—adaptations aimed at stability. Despite a limited sample size and lack of clinical subgroups, results align with age-related gait literature. Findings support the utility of wearable systems like Xsens in capturing clinically relevant gait changes, contributing to normative biomechanical profiling and future mobility interventions. Full article

Objective: Symptomatic flat foot is quite a common pathology in adults. Myofascial release is one of the physiotherapeutic methods that are currently very often used in the treatment of musculoskeletal diseases. This study aimed to assess the impact of myofascial release on the range of motion and functional efficiency of the flat foot in adults. Method: The study involved 60 people with flat feet allocated to four groups and subjected to therapy lasting four weeks: group MRE (Myofascial Release and Exercises; 15 people): myofascial techniques and an exercise programme; group MR (Myofascial Release; 15 people): only myofascial techniques; group E (Exercises; 15 people): only an exercise programme; and the control group C (Control; 15 people): no intervention. Goniometric measurements of the range of motion of the ankle joint and the Foot and Ankle Outcomes Questionnaire (FAOQ) were used to evaluate the effects of the therapy. Results: The range of all tested movements significantly improved after therapy in both feet simultaneously in groups MRE (left foot: dorsiflexion p = 0.017; plantar flexion p = 0.006; inversion p = 0.003; and eversion p = 0.001; right foot: dorsiflexion p = 0.008; plantar flexion p = 0.003; inversion p = 0.008; and eversion p = 0.004) and MR (left foot: dorsiflexion p = 0.001; plantar flexion p = 0.001; inversion p = 0.001; and eversion p = 0.001; right foot: dorsiflexion p = 0.001; plantar flexion p = 0.002; inversion p = 0.001; and eversion p = 0.029). The FAOQ results were significantly better after therapy in groups MRE (p = 0.010), MR (p = 0.001) and E (p = 0.015). Conclusions: In the people studied, the combination of myofascial techniques and exercises (MRE) was the most effective for improving the tested ranges of motion of the ankle joint. Myofascial techniques had a significant impact on the performance of the feet assessed with the FAOQ. Full article

Background: The medial (MG) and lateral gastrocnemius (LG) muscles exhibit differential activation patterns during plantar flexion tasks. However, the influence of range of motion (ROM), exercise type (unilateral vs. bilateral), and limb dominance on muscle activity during heel raise exercises (HREs) remains unclear. Methods: Nineteen physically active adults performed unilateral and bilateral HREs under two ankle ROM conditions: neutral (NROM) and full (FROM). Surface electromyography (EMG) was collected from both legs during each condition and normalized to peak values recorded during overground sprinting. Results: MG activity was significantly higher during the FROM than the NROM, in both the dominant leg (F = 11.55, p < 0.01, η² = 0.47) and the non-dominant leg (F = 6.63, p < 0.05, η² = 0.31), and was not affected by exercise type. In contrast, LG activity increased significantly during unilateral versus bilateral HREs, especially in the dominant leg during the FROM (F = 17.47, p < 0.01, η² = 0.52) and in the non-dominant leg (F = 5.44, p < 0.05, η² = 0.25). Activation ratios (MG:LG) differed significantly between dominant and non-dominant legs only in the unilateral FROM (p = 0.03). MG activation during the unilateral FROM was comparable to sprinting values, highlighting its high neuromuscular demand. Conclusion: The MG and LG respond differently to exercise parameters. The MG is primarily influenced by ROM, whereas the LG is sensitive to both exercise type and limb dominance. These findings emphasize the importance of ROM manipulation and unilateral training to target specific gastrocnemius regions. FROM and unilateral execution optimize gastrocnemius activation, with implications for rehabilitation and performance programs targeting calf musculature. Full article

Concurrent cognitive tasks, such as avoiding visual, auditory, chemical, and electrical hazards, and concurrent motor tasks, such as load carriage, are prevalent in ergonomic settings. Trips are extremely common in the workplace, leading to fatal and non-fatal fall-related injuries. Intrinsic factors, such as attention, fatigue, and anticipation, as well as extrinsic factors, including tasks at hand, affect trip recovery responses. Objective: The purpose of this study was to investigate the ankle joint kinematics in unexpected and expected trip responses during single-tasking (ST), dual-tasking (DT), and triple-tasking (TT), before and after a physically fatiguing protocol among young, healthy adults. Methods: Twenty volunteers’ (10 females, one left leg dominant, age 20.35 ± 1.04 years, height 174.83 ± 9.03 cm, mass 73.88 ± 15.55 kg) ankle joint kinematics were assessed using 3D motion capture system during unperturbed gait (NG), unexpected trip (UT), and expected trip (ET), during single-tasking (ST), cognitive dual-tasking (CDT), motor dual-tasking (MDT), and triple-tasking (TT), under both PRE and POST fatigue conditions. Results: Greater dorsiflexion angles were observed during UT compared to NG, MDT compared to ST, and TT compared to ST. Significantly greater plantar flexion angles were observed during ET compared to NG and during POST compared to PRE. Conclusions: Greater dorsiflexion angles during dual- and triple-tasking suggest that divided attention affects trip recovery. Greater plantar flexion angles following fatigue are likely an anticipatory mechanism due to altered muscle activity and increased postural control demands. Full article

Introduction: Haglund’s deformity, characterized by bony enlargement at the back of the heel, often coincides with Achilles tendon pathology due to impingement on the retrocalcaneal bursa and tendon insertion. Surgical management of Haglund’s deformity with a preexisting Achilles tendon rupture is complex, and understanding the outcomes of this subset of patients is essential for optimizing treatment strategies. Methods: This retrospective study reviewed patients undergoing open surgical management for Haglund’s syndrome between January 2015 and December 2023. Patients with chronic degenerative changes secondary to Haglund’s deformity and a preoperative Achilles tendon rupture were compared to those without. Data on demographics, surgical techniques, weightbearing protocols, and complications were collected. Univariate analysis was performed using χ² or Fisher’s exact test for categorical variables, and the T-test or Wilcoxon rank-sum test for continuous and ordinal variables, with normality assessed via the Shapiro–Wilk test. Results: Four hundred and three patients were included, with 13 having a preoperative Achilles tendon rupture. There was a higher incidence of preoperative ruptures among males. Surgical repair techniques and postoperative weightbearing protocols varied, though were not randomized. Complications included persistent pain, wound breakdown, infection, plantar flexion weakness, and revision surgery. While patients with Haglund’s deformity and a preoperative Achilles tendon rupture demonstrated a trend toward higher complication rates, including postoperative rupture and wound breakdown, these differences were not statistically significant in our analysis. Conclusions: A cautious approach is warranted in managing these patients, with careful consideration of surgical planning and postoperative rehabilitation. While our findings provide valuable insights into managing patients with Haglund’s deformity and preoperative Achilles tendon rupture, the retrospective design, limited sample size of the rupture group, and short duration of follow-up restrict generalizability and the strength of the conclusions by limiting the power of the analysis and underestimating the incidence of long-term complications. Therefore, the results of this study should be interpreted with caution. Further studies with larger patient cohorts, validated functional outcome measures, and comparable follow-up durations between groups are needed to confirm these results and optimize treatment approaches. Full article

The investigation of the neuromuscular components of fatigue in team sports, especially in developmental ages, is limited. This study aimed to examine the neuromuscular fatigue and recovery patterns in prepubertal and adult female handball players, focusing on the soleus (SOL) and tibialis anterior (TA) muscles. Fifteen prepubertal (11.1 ± 0.9 years) and fourteen adult (22.0 ± 3.4 years) females performed a sustained isometric plantar flexion at 25% of maximal voluntary contraction (MVC) until exhaustion. The electromyographic (EMG) activity of the SOL and TA, torque, and central activation ratio (CAR) were recorded throughout the experiment. Endurance time was similar between groups (girls: 104 ± 93.5 s; women: 94.4 ± 30.2 s, p > 0.05), and both demonstrated progressive increases in muscle activation, without significant group differences for SOL and TA EMG (p > 0.05). Following fatigue, the torque and soleus (SOL) EMG activity decreased significantly compared to the pre-fatigue values in both groups (p < 0.001) and recovered (p > 0.05) in prepubertal and adult females within the first 3 and 6 min, respectively. The CAR remained unchanged over time, without significant differences observed between age groups (p > 0.05). These findings suggest that neuromuscular responses to fatigue are comparable between prepubertal and adult females, but recovery is significantly faster in prepubertal girls. Consequently, these findings underscore the need for age-specific recovery strategies in training programs, with tailored exercise-to-rest ratios to enhance performance and reduce fatigue during handball-specific activities. Full article