This study was aimed to analyse the lower limb kinematics during the change of direction (COD) performance with the dominant (DL) and non-dominant (NDL) leg using linear (traditional kinematics) and nonlinear (Self Organising Map-based cluster analysis) approaches. Three 5-0-5 COD performances with the DL and three with the NDL were performed by 23 (aged 21.6 ± 2.3 years) collegiate athletes. No significant difference was observed between the COD duration, and approach speed of DL and NDL. Significantly greater ankle abductions, knee and hip external rotations were identified in COD with DL, compared to NDL (p < .001, d > 0.8). Self Organising Maps portrayed a completely different coordination pattern profile during change of direction performance with the DL and NDL. The cluster analysis illustrated similar inter-individual coordination patterning when participants turned with their DL or NDL. No visible relationship was observed in the cluster analysis of the lower limb joint angles and angular velocities. Outcomes of this study portrayed that coordination patterning (combination of joint angles and the rate of change of angles) could portray the movement patterning differences in different tasks, while a sole investigation on the joint angles or angular velocities may not reveal the underlying mechanisms of movement patterning.
- MeSH
- Leg * physiology MeSH
- Biomechanical Phenomena MeSH
- Lower Extremity * physiology MeSH
- Functional Laterality * physiology MeSH
- Ankle physiology MeSH
- Humans MeSH
- Young Adult MeSH
- Motor Skills * physiology MeSH
- Nonlinear Dynamics MeSH
- Movement physiology MeSH
- Cluster Analysis MeSH
- Athletic Performance * physiology MeSH
- Check Tag
- Humans MeSH
- Young Adult MeSH
- Male MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
BACKGROUND: Muscle strength and postural control are essential components for performing daily living activities, particularly in older adults, and can therefore serve as screening tools for assessing fall risk in this population. METHODS: The aim of this quasi-experimental study was to evaluate the impact of a 12-week exercise intervention followed by a 2-week detraining period on lower limb strength and postural stability in older adults. The study involved 38 community-dwelling participants of Central European origin over 60 years of age. Participants underwent the measurements consisting of assessments of knee flexors and extensors strength (isokinetic dynamometer, 90° range of motion, 60°/s angular velocity, Humac Norm CSMI, Stoughton MA, USA), toe grip strength (toe grip dynamometer, Takei Scientific Instruments, Niigata, Japan), and postural stability (narrow stand, 30 s, Kistler, Switzerland). Testing was repeated three times during the study (pre-intervention, post-intervention, and post-detraining). Participants were separated into 3 groups according to the type of training: resistance training group (n = 13), proprioceptive training group (n = 14), and endurance training group (n = 11). The intervention program lasted 12 weeks, two 60-min sessions per week. A linear mixed model (LMM) predicted a change in postural stability after the resistance, proprioceptive, and endurance exercise interventions were applied. RESULTS: Results showed that knee extensor strength normalized to body mass significantly increased in the resistance training group post-intervention (p = 0.01). Toe grip strength was significantly higher after the intervention in the endurance training group (p = 0.02). A statistically significant increase in knee flexor strength was observed in the proprioceptive training group (p = 0.01). The 2-weeks detraining period revealed no statistically significant loss in training gains. The LMM found different predictions of postural stability changes related to knee extensor strength after each type of training intervention. The final LMM model explains well the variability of the dependent variable R2 = 0.866. CONCLUSIONS: These results highlight the unique characteristics of specific exercise interventions in enhancing muscular strength and postural stability, which are critical for fall prevention among older adults.
- MeSH
- Time Factors MeSH
- Exercise * physiology MeSH
- Lower Extremity * physiology MeSH
- Middle Aged MeSH
- Humans MeSH
- Linear Models MeSH
- Resistance Training * methods MeSH
- Postural Balance * physiology MeSH
- Aged, 80 and over MeSH
- Aged MeSH
- Muscle Strength * physiology MeSH
- Exercise Therapy * methods MeSH
- Accidental Falls prevention & control MeSH
- Check Tag
- Middle Aged MeSH
- Humans MeSH
- Male MeSH
- Aged, 80 and over MeSH
- Aged MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
METHODS: A total of 181 young male athletes were recruited and categorized according to sport specialization (soccer or athletics) and age categories (U15, U17 or U19). Isokinetic strength was measured as peak muscle torque (PT), normalized to body mass, for the knee extensors (PTKE) and knee flexors (PTKF) during concentric muscle contraction at three angular velocities (60°s-1. 180°s-1. 300°s-1). Vertical jump performance was measured during a countermovement jump with arms fixed (CMJ) and a squat jump (SJ). RESULTS: Significantly higher values of bilateral asymmetry (BA) of PTKF for angular velocity 60°s-1 and 180°s-1 were found in the athletics group compared to the soccer group in the U17 category (14.40% to 16.02% vs 9.07% to 10.45%). Significantly higher values of BA for angular velocity 300°s-1 for both PTKE and PTKF were found in the U15 compared to U19 category. Significantly higher values of H:Q ratio at all angular velocity except for the non-dominant leg in the highest angular velocity in soccer compared to the athletes in the U17 category were found. Soccer players exhibited significantly higher values of PTKF compared to those in athletics and jump height in the U17 category. CONCLUSION: Soccer players displayed increased isokinetic strength and more balanced BA compared to the athletics group. Physiotherapists and strength coaches should focus on younger age groups, especially U15, due to the higher incidence of BA and lower relative strength regardless of specialization.
- MeSH
- Soccer * physiology MeSH
- Muscle, Skeletal physiology MeSH
- Humans MeSH
- Adolescent MeSH
- Plyometric Exercise MeSH
- Specialization * MeSH
- Athletic Performance * physiology MeSH
- Muscle Strength * physiology MeSH
- Torque MeSH
- Age Factors MeSH
- Check Tag
- Humans MeSH
- Adolescent MeSH
- Male MeSH
- Publication type
- Journal Article MeSH
Objectives: The relationship between the isokinetic maximal strength of internal or external shoulder rotation and serve speed in tennis is well established, yet the influence of segmental mass, height, and high-speed shoulder rotation strength on serve performance in junior players remains unclear. This study aimed to investigate the relationship between concentric or eccentric isokinetic shoulder strength, segmental mass, height, and first-serve speed aimed at the T-target zone. Methods: Fifteen male junior competitive tennis players (mean ± SD: age 15.9 ± 0.9 years; height: 180.1 ± 7.2 cm; body mass: 66.1 ± 5.7 kg) were assessed for maximal isokinetic strength during concentric and eccentric internal and external shoulder rotations. Segmental mass (arm, leg, and trunk) was measured using dual-energy X-ray absorptiometry, and serve speed was recorded using a radar gun. Results: Concentric shoulder rotations at 210°/s demonstrated significant positive correlations with serve speed for both external (ρ = 0.71, p ≤ 0.01) and internal rotation (ρ = 0.61, p ≤ 0.05). Although lean arm mass partially mediated the relationship between shoulder strength and serve speed (indirect effect = 0.502, 95% CI: -0.156 to 1.145), this mediation effect was not statistically significant. Height was moderately correlated with serve speed (ρ = 0.68, p ≤ 0.01) but did not moderate the relationship between shoulder strength and serve speed. Conclusions: Concentric shoulder strength at higher angular velocities and segmental mass contribute to serve speed in junior tennis players. While height provides structural advantages, strength and lean mass play important roles, emphasizing the need for targeted training programs.
- Publication type
- Journal Article MeSH
PURPOSE: The present study aimed to investigate a) the associations between bilateral performance utilizing countermovement jump (CMJ), squat jump (SJ), speed and unilateral CMJ, isokinetic peak torque in knee extension and flexion with angular velocities of 60°/s and 180°/s and tensiomyography (TMG) parameters; b) whether the asymmetries derived from unilateral tests are associated with bilateral CMJ, SJ and speed in elite female soccer players. METHODS: Thirty-five elite female soccer players (average age: 20 ± 5 years) completed CMJ, SJ, speed, isokinetic muscle strength and TMG tests. RESULTS: Compared to the non-dominant leg, the dominant leg demonstrated greater peak torque output in both knee flexion (7.4%) and knee extension (5.6%) isokinetic tasks, as well as m. vastus medialis contraction time (7.6%), and soccer-specific agility test (4.1%). Conversely, the hamstring to quadriceps peak torque ratio at 180°/s (8.5%) was significantly greater in the non-dominant leg. The associations between CMJ, SJ and speed performance were positive and ranged from weak (r = 0.350) to high (r = 0.710). For speed and TMG-derived variables, correlations were negative and ranged from weak (r = -0.345, p = 0.042, for vastus medialis contraction time) to moderate (r = -0.530, p = 0.001, for biceps femoris contraction time). Furthermore, both bilateral CMJ and SJ negatively correlated with TMG-derived variables, ranging from weak (r = -0.350, p = 0.039, for vastus lateralis contraction time) to moderate (r = -0.537, p = 0.003, for rectus femoris contraction time). CONCLUSION: The overall significant, albeit inconsistent, correlations between the diverse performance scores obtained highlight the necessity for a multifaceted and thorough diagnostic strategy in female soccer players.
- Publication type
- Journal Article MeSH
BACKGROUND: Turning in place is a challenging motor task and is used as a brief assessment test of lower limb function and dynamic balance. This review aims to examine how research of instrumented analysis of turning in place is implemented. In addition to reporting the studied population, we covered acquisition systems, turn detection methods, quantitative parameters, and how these parameters are computed. METHODS: Following the development of a rigorous search strategy, the Web of Science and Scopus were systematically searched for studies involving the use of turning-in-place. From the selected articles, the study population, types of instruments used, turn detection method, and how the turning-in-place characteristics were calculated. RESULTS: Twenty-one papers met the inclusion criteria. The subject groups involved in the reviewed studies included young, middle-aged, and older adults, stroke, multiple sclerosis and Parkinson's disease patients. Inertial measurement units (16 studies) and motion camera systems (5 studies) were employed for gathering measurement data, force platforms were rarely used (2 studies). Two studies used commercial software for turn detection, six studies referenced previously published algorithms, two studies developed a custom detector, and eight studies did not provide any details about the turn detection method. The most frequently used parameters were mean angular velocity (14 cases, 7 studies), turn duration (13 cases, 13 studies), peak angular velocity (8 cases, 8 studies), jerkiness (6 cases, 5 studies) and freezing-of-gait ratios (5 cases, 5 studies). Angular velocities were derived from sensors placed on the lower back (7 cases, 4 studies), trunk (4 cases, 2 studies), and shank (2 cases, 1 study). The rest (9 cases, 8 studies) did not report sensor placement. Calculation of the freezing-of-gait ratio was based on the acceleration of the lower limbs in all cases. Jerkiness computation employed acceleration in the medio-lateral (4 cases) and antero-posterior (1 case) direction. One study did not reported any details about jerkiness computation. CONCLUSION: This review identified the capabilities of turning-in-place assessment in identifying movement differences between the various subject groups. The results, based on data acquired by inertial measurement units across studies, are comparable. A more in-depth analysis of tests developed for gait, which has been adopted in turning-in-place, is needed to examine their validity and accuracy.
Background: Objective criteria to accurately evaluate the ability of a patient to make a risk-free return to their previous level of activity after anterior cruciate ligament reconstruction (ACLR) and to progress through stages of the rehabilitation process are still widely discussed. Objective: The goal of the study was to investigate the functional status of non-elite football players 6 months after ACLR based on the Functional Movement Screen test (FMS) and side-to-side differences of isokinetic quadriceps and hamstring peak torque between the operated (OP) and non-operated (NOP) extremities. Methods: A total of 35 football players (male:female ratio 31:4, mean age 24.7 ± 2.8 years) who had undergone primary and isolated ACLR were assessed 6 months (mean 6.1 ± 2.6) after surgery. Functional performance evaluation included the FMS test and isokinetic quadriceps/hamstring peak torque values examined using the Biodex Testing System at angular velocities of 60 deg/s and 180 deg/s. In addition, side-to-side differences for flexion and extension at both angular velocities were calculated by the limb symmetry index. Results: In the functional assessment, the overall score of the FMS test was 15.34 ± 2.60. Moreover, inter-extremity differences in all isokinetic strength tests were statistically significant. Isokinetic strength peak torques of quadriceps and hamstring of NOP were significantly higher than those of OP at both angular velocities (p < .001). The limb symmetry index results for recorded peak torques at 60 deg/s were 75% in extension and 88% in flexion and at 180 deg/s were 79% in extension and 86% in flexion. Conclusion: The presented data indicate explicit inter-extremity muscles strength differences and disturbances in global movement patterns after ACLR. Delayed recovery of muscle strength and disparities between the OP and NOP limbs 6 months after ACLR may undermine the patient's readiness to return to preoperative activity.
- MeSH
- Quadriceps Muscle MeSH
- Adult MeSH
- Soccer injuries MeSH
- Humans MeSH
- Return to Sport MeSH
- Patient Acuity MeSH
- Anterior Cruciate Ligament Reconstruction * methods rehabilitation MeSH
- Treatment Outcome MeSH
- Hamstring Muscles MeSH
- Check Tag
- Adult MeSH
- Humans MeSH
- Male MeSH
- Female MeSH
- Publication type
- Clinical Study MeSH
Impact force and maximum velocity are important indicators of kick efficiency. Therefore, this systematic review compared the front kick (FK) and roundhouse kick (RK), including their impact force, maximum velocity, angular velocity, and execution time, considering various target types and experience levels. Following PRISMA guidelines, the Web of Science, SportDiscus, and PubMed were systematically searched for articles published from January 1982 to May 2022. Normalized kicking values were compared using one-way ANOVA. Eighteen articles included FKs (sample: 113 elite men, 109 sub-elite men, and 46 novices), and twenty-five articles included RKs (sample: 238 elite men, 143 sub-elite men, and 27 novice men). The results indicate that the impact force of the FK were 47% (p < 0.01), 92% (p < 0.01), and 120% (p < 0.01) higher than those of the RK across novice, sub-elite, and elite groups, respectively. Moreover, the maximum foot velocity of the RK was 44% (p < 0.01) and 48% (p < 0.01) higher than that of the FK for the sub-elite and elite groups, respectively. Furthermore, the elite group had 65% (p < 0.01) higher knee extension angular velocity with the RK than with the FK and 138% (p < 0.01) higher hip extension angular velocity with the FK than with the RK. In summary, the findings suggest that the FK is more effective in generating forceful kicks, while the RK has the potential for rapid execution.
- Publication type
- Journal Article MeSH
- Review MeSH
This study aimed to increase understanding of the biomechanics and dynamics of the upper limbs during the contact phase of the round-off (RO) performed using three techniques. Twenty female gymnasts performed six successful RO trials in each condition: parallel, T-shape and reverse. Kinetic and kinematic data were collected for each trial. All analyses focused on the contact phase for each hand. Continuous joint profiles examined the dynamics of these tasks as well as the kinetic sequencing. In each case, joint angles, angular velocity, moments and powers at the wrist and elbow joint were reported. Difference between the contact phases of the techniques was examined using a one-way ANOVA SPM. The T-shape technique demonstrated negative power at the wrist during contact; however, the elbow joint compensated with a significantly greater positive power generation during the propulsive phase, suggesting a more effective technique compared to the reduced powers of the reverse and parallel. The order of the peak joint powers during the contact phase, the reverse technique, demonstrated a proximal to distal sequence, in contrast to the distal to proximal for the other techniques. These findings highlight the task-specific coordinative structures during this closed chained action.
- MeSH
- Biomechanical Phenomena MeSH
- Gymnastics * MeSH
- Upper Extremity MeSH
- Humans MeSH
- Elbow Joint * MeSH
- Hand MeSH
- Check Tag
- Humans MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
BACKGROUND: The physical characteristics of golfers have a strong relationship with the clubhead speed (CHS), which is the main indicator of energy produced during a golf swing. However, perennial observations of development in CHS, physical characteristics, and body composition, and their long-term effects on CHS are lacking. Therefore, this study aimed to evaluate the lower body physical characteristics and body composition parameters and their relationship with clubhead speed during one and over a two-year period in junior golfers. METHODS: Nineteen skilled, male, junior golfers participated in this study. RESULTS: A significant positive relationship (P<0.05) was found between improvement in CHS and increase in the body height (r=0.56), increase in peak power of the countermovement jump (r=0.55), and squat jump (r=0.52). A near-significant positive relationship was found between improvement in CHS and increases in the fat-free mass (r=0.42; P=0.06) and peak torque of the knee extensor at an angular velocity of 60° s-1 (r=0.44; P=0.07). CONCLUSIONS: Thus, we recommend that golf coaches work on muscle strengthening and conditioning with their players, focusing on: 1) the increase of the active muscle mass as opposed to the total body mass in relation to the acceleration of CHS; and 2) exercises to develop the muscle power (vertical jumping) and maximum lower limb strength (knee extension).
- MeSH
- Biomechanical Phenomena MeSH
- Golf * physiology MeSH
- Humans MeSH
- Posture MeSH
- Body Composition MeSH
- Athletic Performance * physiology MeSH
- Muscle Strength physiology MeSH
- Check Tag
- Humans MeSH
- Male MeSH
- Publication type
- Journal Article MeSH
