Dominant Leg Research Articles

Assessing the reliability of biomechanical variables during a horizontal deceleration task in healthy adults

ABSTRACT Horizontal deceleration technique is an underpinning factor to musculoskeletal injury risk and performance in multidirectional sport. This study primarily assessed within- and between-session reliability of biomechanical and performance-based aspects of a horizontal deceleration technique and secondarily investigated the effects of limb dominance on reliability. Fifteen participants completed four horizontal decelerations on each leg during test and retest sessions. A three-dimensional motion analysis system was used to collect kinetic and kinematic data. Completion time, ground contact time, rate of horizontal deceleration, minimum centre of mass height, peak eccentric force, impulse ratio, touchdown distance, sagittal plane foot and knee angles at initial contact, maximum sagittal plane thorax angle, and maximum knee flexion moment were assessed. Coefficients of variation (COV) and intraclass correlation coefficients (ICC) were used to assess within- and between-session reliability, respectively. Seven variables showed “great” within-session reliability bilaterally (COV ≤9.13%). ICC scores were ‘excellent’ (≥0.91; n = 4), or ‘good’ (0.76-0.89; n = 7), bilaterally. Limb dominance affected five variables; three were more reliable for the dominant leg. This horizontal deceleration task was reliable for most variables, with little effect of limb dominance on reliability. This deceleration task may be reliably used to assess and track changes in deceleration technique in healthy adults.

Assessment of Muscle Stiffness Using the MyotonPro: Effects of Fatigue on Vastus Lateralis and Medialis Muscles.

The investigation of soft tissue stiffness has garnered increasing interest due to its potential applications in detecting tissue conditions, monitoring therapy effects, and preventing sports injuries. This study utilized the MyotonPro as a reliable measurement device to assess muscle stiffness and muscle frequency in the vastus lateralis and medialis muscles of both the dominant and non-dominant legs. Sixteen young, healthy subjects (seven males and nine females, age 25 ± 3.46 years) participated in this study. To induce maximal muscle fatigue, the vastus lateralis and vastus medialis muscles were subjected to a 30 kg load using a single-leg leg press. Pre- and post-fatigue measurements were conducted by two testers on the dominant and non-dominant legs, respectively, employing the MyotonPro. We revealed a significant increase in muscle stiffness after maximal muscle fatigue. Specifically, on the dominant side, the vastus lateralis exhibited a stiffness increase of 6.5%, while the vastus medialis showed a 6.3% increase. On the non-dominant side, the vastus lateralis demonstrated a 7.6% increase, and the vastus medialis exhibited a 6.7% increase in muscle stiffness. Furthermore, muscle frequency increased by 8.6% (vastus lateralis) and 13.5% (vastus medialis) on the dominant side and by 15.1% (vastus lateralis) and 6.3% (vastus medialis) on the non-dominant side. The reliability of the measurements varied, with Cronbach's alpha values ranging from inadequate 0.49 to very good 0.88. This study affirms the efficacy of the MyotonPro as a measurement device for assessing muscle stiffness and establishes its reliability. The observed increase in muscle stiffness after maximal muscle fatigue, accompanied by changes in muscle frequency, underscores the device's utility. However, further research is warranted to validate the reproducibility of these findings and explore additional facets of the muscular response to fatigue.

Symmetric unipedal balance in quiet stance and dynamic tasks in older individuals

Previous evidence of increased difference of muscular strength between the dominant and non-dominant legs in older adults suggests the possibility of dissimilar balance control between the legs (between-leg asymmetry) associated with aging. In the current investigation, we evaluated between-leg asymmetries in older adults when performing quiet and dynamic balance tasks. Fifty-two physically active and healthy older adults within the age range of 60 to 80 years were recruited. Participants performed balance tasks in unipedal stance, including quiet standing and cyclic sway (rhythmic oscillation) of the non-supporting leg in the anteroposterior or mediolateral directions, producing foot displacements with amplitudes of 20 cm paced in 1 Hz through a metronome. Body balance was evaluated through trunk accelerometry, by using the sensors embedded into a smartphone fixed at the height of the 10th-12th thoracic spines. Analysis revealed lack of significant differences in balance control between the legs either when comparing the right versus left or the preferred versus non-preferred legs, regardless of whether they were performing quiet stance or dynamic tasks. Further examination of the data showed high between-leg correlation coefficients (rs range: 0.71–0.84) across all tasks. Then, our results indicated symmetric and associated between-leg balance control in the examined older adults.

Jumping towards field-based ground reaction force estimation and assessment with OpenCap

Low-cost and field-viable methods that can simultaneously assess external kinetics and kinematics are necessary to enhance field-based biomechanical monitoring. The aim of this study was to determine the accuracy and usability of ground reaction force (GRF) profiles estimated from segmental kinematics, measured with OpenCap (a low-cost markerless motion-capture system), during common jumping movements. Full-body segmental kinematics were recorded for fifteen recreational athletes performing countermovement, squat, bilateral drop, and unilateral drop jumps, and used to estimate vertical GRFs with a mechanics-based method. Eleven distinct performance-, fatigue-, or injury-related GRF variables were then validated against a gold-standard force platform. Across jumping movements, a total of six and three GRF variables were estimated with a bias or limits of agreement <5 % respectively. Bias and limits of agreement were between 5 and 15 % for seventeen and nineteen variables respectively. Moreover, we show that estimated force variables with a bias <15 % can adequately assess the within-athlete changes in GRF variables between jumping conditions (arm swing or leg dominance). These findings indicate that using a low-cost and field-viable markerless motion capture system (OpenCap) to estimate and assess GRF profiles during common jumping movements is approaching acceptable limits of accuracy. The presented method can be used to monitor force variables of interest and examine underlying segmental kinematics. This application is a jump towards researchers and sports practitioners performing biomechanical monitoring of jumping efficiently, regularly, and extensively in field settings.

Association between fat and fat-free body mass indices on shock attenuation during running

High amplitudes of shock during running have been thought to be associated with an increased injury risk. This study aimed to quantify the association between dual-energy X-ray absorptiometry (DEXA) quantified body composition, and shock attenuation across the time and frequency domains. Twenty-four active adults participated. A DEXA scan was performed to quantify the fat and fat-free mass of the whole-body, trunk, dominant leg, and viscera. Linear accelerations at the tibia, pelvis, and head were collected whilst participants ran on a treadmill at a fixed dimensionless speed 1.00 Fr. Shock attenuation indices in the time- and frequency-domain (lower frequencies: 3–8 Hz; higher frequencies: 9–20 Hz) were calculated. Pearson correlation analysis was performed for all combinations of DEXA and attenuation indices. Regularised regression was performed to predict shock attenuation indices using DEXA variables. A greater power attenuation between the head and pelvis within the higher frequency range was associated with a greater trunk fat-free mass (r = 0.411, p = 0.046), leg fat-free mass (r = 0.524, p = 0.009), and whole-body fat-free mass (r = 0.480, p = 0.018). For power attenuation of the high-frequency component between the pelvis and head, the strongest predictor was visceral fat mass (β = 48.79). Passive and active tissues could represent important anatomical factors aiding in shock attenuation during running. Depending on the type and location of these masses, an increase in mass may benefit injury risk reduction. Also, our findings could implicate the injury risk potential during weight loss programs.

Hip adduction and abduction strength profiles in elite and sub-elite female soccer players according to players level and leg limb-dominance

BackgroundUnderstanding the hip adduction and abduction strength in female soccer players is crucial for performance enhancement and injury prevention. This study compares the strength profiles in these muscle groups between elite and sub-elite female soccer players and assesses the impact of leg limb-dominance.MethodsA descriptive-comparative study was employed. Eighty-two female soccer players were evaluated. Isometric hip-adduction and abduction strength were measured using a handheld dynamometer.ResultsFemale elite and sub-elite soccer players displayed a mean and standard deviation (SD) on isometric hip-adductor strength for dominant (3.19 Nm/kg ± 0.69 vs. 2.40 Nm/kg ± 0.67) and non-dominant leg (3.32 Nm/kg ± 0.76 versus 2.42 Nm/kg ± 0.70), respectively. For isometric hip-abductor strength in elite and sub-elite players, a mean and SD of dominant (2.86 Nm/kg ± 0.56 vs. 2.07 Nm/kg ± 0.50) and non-dominant (2.80 Nm/kg ± 0.59 vs. 2.04 Nm/kg ± 0.43). In essence, elite players were stronger than sub-elite players on isometric hip-adduction (mean difference [MD] = 0.82 Nm/kg, CI95% = 0.42–1.12) and abduction (MD = 0.83 Nm/kg, CI95% = 0.54- 1.12) both in dominant and non-dominant, leg, whereas no differences existed for hip adduction:abduction ratios between groups and legs.ConclusionsElite female athletes exhibited greater strength than sub-elite female players in both hip adduction and abduction, whereas adduction:abduction ratio values did not differ between the two groups or between different legs.

The effects of eccentric training on hamstring flexibility and strength in young dance students

The objective of this research is to examine the impact of eccentric training on hamstring flexibility and strength in young dancers during the concluding stages of their foundational dance training program. A total of 24 female, second-year dance students from Hebei Normal University were selected as participants. They were divided into three distinct groups: Nordic hamstring exercise and single-leg deadlift group (NHE&SLD), forward bending exercises and standing leg lift group (FBE&SLL), and a control group (CG). The study was designed around a 6-week training regimen. An isokinetic dynamometer was used to measure seated knee flexor–extensor strength, while electronic goniometry was employed to measure hamstring flexibility in the supine position. Paired sample t-tests were conducted within each group, and one-way analysis of covariance (ANCOVA) was utilized for comparisons between groups. In the NHE&SLD group, significant disparities were observed in both concentric (T = − 5.687, P = 0.001) and eccentric (T = − 3.626, P = 0.008) hamstring strength pre and post-intervention. The pre-intervention dominant leg concentric strength test values significantly influenced the post-intervention outcomes (F = 5.313, P = 0.001, η2 = 0.840). Similarly, the pre-intervention dominant leg eccentric strength test values impacted the post-intervention results (F = 4.689, P = 0.043, η2 = 0.190). Following the intervention, the NHE&SLD group displayed marked changes in the active straight leg raising angle on both left (T = − 4.171, P = 0.004) and right (T = − 6.328, P = 0.001) sides. The FBE&SLL group also revealed significant changes in the active straight leg raising angle on both left (T = − 4.506, P = 0.003) and right (T = − 4.633, P = 0.002) sides following the intervention. The pre-intervention left leg concentric strength test value significantly influenced the post-intervention outcomes (F = 25.067, P = 0.001, η2 = 0.556). Likewise, the pre-intervention right leg eccentric strength test value significantly influenced the post-intervention results (F = 85.338, P = 0.01, η2 = 0.810). Eccentric training can better enhance the flexibility and strength of hamstring muscles in dance students. Traditional stretching training significantly improves the flexibility of the hamstring muscles. Eccentric training has more training benefits than traditional stretching training. It is recommended for dance students to use eccentric training when increasing hamstring flexibility and strength.

Effects of Adding Mechanical Vibration and a Stick on Acceleration and Movement Variability during a Slide-Board Skating Exercise: Differences between the Dominant and Non-Dominant Legs

The aim of the present study was to analyse differences in acceleration and movement variability caused by adding whole-body vibration (WBV) and an implement (stick) while performing a slide-board (SB) skating exercise. A total of 10 professional ice-hockey players (age 20.4 ± 2.07 years) participated in the study. Participants performed 30 s of lateral sliding on a slide vibration board (SVB). Four conditions were analysed: no vibration and no stick (NVNS), no vibration with a stick (NVS), vibration without a stick (VNS) and vibration with a stick (VS). Peak acceleration, mean acceleration and movement variability (MV) were analysed in the dominant and non-dominant legs in each condition. Peak acceleration was higher in the non-dominant leg (p &lt; 0.01). However, MV was higher in the dominant leg (p &lt; 0.01). Regarding differences between conditions, mean acceleration was higher in VNS and VS than in NVS (p &lt; 0.05). Regarding MV (sample entropy), there were differences in NVNS compared to VNS and VS (p &lt; 0.01) and in NVS compared to VNS and VS (p &lt; 0.01), with the values being superior in VNS and VS. The addition of WBV during an SB skating exercise results in an increase in MV and mean acceleration. The dominant leg shows greater MV regardless of the addition of vibration and a stick during sliding on an SVB.

Effects of plyometric jump training on measures of physical fitness and lower-limb asymmetries in prepubertal male soccer players: a randomized controlled trial

BackgroundHigh level of physical fitness is a paramount soccer performance factor. As such, developing key components of physical fitness such as sprinting, jumping, and change of direction (CoD) at an early age empowers both short- and long-term performance success. Although previous research in prepubertal male soccer players has reported physical fitness performance enhancements following plyometric jump training (PJT), the effects on inter-limb asymmetries remain unclear.ObjectiveTo assess the effects of PJT on measures of physical fitness and inter-limb asymmetries in prepubertal male soccer players.MethodsA total of 27 participants were recruited, and randomly assigned to either a PJT group (n = 13; age = 12.7 ± 0.2 years; maturity offset = -1.6 ± 0.7) or an active control group (CG) (n = 14; age = 11.8 ± 0.4 years; maturity offset = -2.51 ± 0.61). The training intervention lasted eight-week and was conducted during the in-season period, with twice-weekly sessions. Physical fitness tests were conducted before and after the intervention, including the 505 change-of-direction (CoD; [505 CoD test]), countermovement-jump (CMJ) height, standing-long-jump (SLJ) distance, and single-leg hop test for distance with dominant (SHTD-D) and non-dominant legs (SHTD-ND). A jump-based asymmetry score was calculated as the difference between HTD and HTND.ResultsANCOVA analysis revealed significant between-group differences in all physical fitness measures at post-test. Specifically, the PJT group showed significant large improvements in CMJ height, SLJ distance, HTD and HTND, and CoD speed (d = 0.84 to 2.00; ∆1.05% to 16.85%). Moreover, the PJT group showed a significant, small reduction in the inter-limb asymmetry score (d = 0.43; ∆-45.21%). In contrast, no significant changes were reported in the CG between pre-and post-tests (d = 0.07 to 0.24; ∆0.21% to 0.98%).ConclusionsThe incorporation of PJT into the training schedules of prepubertal male soccer players resulted in positive effects on various measures of physical fitness. Furthermore, our findings suggest that PJT can reduce lower-limb asymmetry, which could potentially decrease the risk of lower limb injuries.Trial registrationThis study does not report results related to healthcare interventions using human participants and therefore it was not prospectively registered.

Differences in Achilles tendon mechanical properties between professional ballet dancers and collegiate athletes utilizing shear wave elastography.

To report normative stiffness parameters obtained using shear wave elastography in dorsiflexion from the Achilles tendons in asymptomatic professional ballet dancers and compare them with college-level athletes. An Institutional Review Board (IRB)-approved study consists of 28 professional ballet dancers and 64 asymptomatic collegiate athletes. The athletes were further subdivided into runner and non-runner disciplines. Shear wave elastography (SWE) measurements were made in maximum ankle dorsiflexion position. Forty-eight (52%) males and 44 (48%) females were examined with an overall mean age of 22.2 (± 3.8 years). There were no significant SWE differences between dominant and non-dominant legs in both groups and comparing spin vs. non-spin leg of ballet dancers (p > 0.05). Ballet dancers had significantly higher short-axis velocity values than runners and non-runners (2.34 m/s increase and 2.79 m/s increase, respectively, p < 0.001). Long-axis velocity was significantly higher in ballet dancers compared to non-runners (by 0.80 m/s, p < 0.001), but was not different between ballet dancers and runners (p > 0.05). Short-axis modulus was significantly higher in dancers compared to runners and non-runners (by 135.2 kPa and 159.2 kPa, respectively, p < 0.001). Long-axis modulus (LAM) was not significantly different in ballet dancers when compared to runners. Asymptomatic professional ballet dancers exhibit greater short-axis tendon stiffness compared to athletes and greater long-axis tendon stiffness compared to non-runners but similar to runners. The functional benefit from elevated short-axis stiffness in dancers is not clear but may be related to greater axial loading and adaptations of the tendon matrix.

School Scoliosis Screening: The Influence of Dominant Limbs and Gender

This study aimed to examine whether (a) there is an association of the dominant hand (DH) and leg (DL) with the side of the primary angle of trunk rotation (ATR A) and (b) there are any differences between boys and girls in the degree of the angle of trunk rotation (ATR) and the dominant hand and leg. One thousand sixty-five (age: 14 ± 3 years; height: 162 ± 13 cm; weight: 56 ± 18.7 kg; BMI: 21.18 ± 5.07) secondary school children participated in this study. Of the participants, 52.5% (n = 559) were male students (age: 14 ± 2 years; height: 166 ± 16 cm; weight: 58.7 ± 22.6 kg; BMI: 21.41 ± 5.61), and 47.5% (n = 506) were female students (age: 14 ± 3 years; height: 159.5 ± 8.5 cm; weight: 53.9 ± 14.8 kg; BMI: 21.03 ± 4.38). The ATR was measured with a scoliometer. Boys were taller and heavier (p = 0.001) and had more left DLs (p = 0.039) than girls. Girls were biologically more mature (p = 0.002), also having higher measurements for the ATR A (p = 0.004) and secondary angle of trunk rotation (ATR B) (p = 0.023) degrees compared to boys. In the general sample, only in boys, there was a significant association between the DH (p = 0.012) and DL (p = 0.001) with the ATR A side. Also, within the scoliotic group, only in boys, there was a significant association between the DH (p = 0.048) and DL (p = 0.024) with the ATR A. In conclusion, girls had higher measurements for the ATR than boys, but cross laterality was found only in boys. The results suggest different progression patterns of ATR between genders during their growth. Future research should focus on examining other possible progression mechanisms.

The impact of a multicomponent training program on physical fitness and joint injuries in Spanish male professional soccer players

ABSTRACT This study aimed to assess the effects of a multicomponent training program (ProSAS) on selected measures of physical fitness and joint injuries in Spanish male professional soccer players. Twenty-six professional soccer players (age: 25.2 ± 3.1 years) were randomly assigned to either the experimental (EG; n = 16) or control group (CG; n = 10). Y-balance test (YBT), Single leg countermovement jump (SLCMJ), Single leg hop for distance test (SLH), Side-hop test (SH), Speedy jump test (SpJ), Agility T-test (TT) and Lower extremity functional test (LEFT) were performed before and after an 8-weeks training period. Additionally, any joint injury occurring during the intervention period were recorded. Significant improvements in the EG in all tests (p = 0.001 to p = 0.014), except for SLCMJ (p = 0.632) with the dominant leg were observed. CG displayed decreases in SLCMJ with the non-dominant leg (p = 0.014), SH for both legs (p = 0.001 to p = 0.050), TT (p = 0.005), and LEFT (p = 0.001). Inter-groups differences revealed better results for the EG in all variables (p = 0.001 to p = 0.008) except from SLCMJd (p = 0.555). Moreover, the EG exhibited lower joint injury incidence and burden compared to the CG (p < 0.05). These findings suggest that the ProSAS is an effective multicomponent program to improve variables related to risk of joint injuries, and consequently, to reduce the incidence and burden of these injuries in professional soccer players.

Absolute and Normalized Normative Torque Values of Knee Extensors and Flexors in Healthy Trained Subjects: Asymmetry Questions the Classical Use of Uninjured Limb as Reference

To provide normative values of maximal isometric torque of knee extensors and flexors measured at 80° of knee flexion and to characterize the results in healthy subjects practicing activities at risk of anterior cruciate ligament rupture. Seventy-four trained volunteers (35 male and 39 female) aged 18 to 41 years were recruited. They alternately performed 3 maximal voluntary isometric contractions of knee extension and flexion. The maximal voluntary isometric contraction net torque was computed as the mean value of the peak torques recorded over the 3 trials. For women, the absolute torque for extensors was 143.5 ± 34.4 N⋅m (range, 87.7-253.1 N⋅m) and 66.8 ± 13.8 N⋅m (range, 37.5-93.1) for flexors. For men, the absolute torque for extensors was 199.8 ± 47.3 N⋅m (range, 99.3-311.5 N⋅m) and 89.8 ± 21.0 N⋅m (range, 51.8-137.2 N⋅m) for flexors. For women, the body mass normalized torque for extensors was 2.20 ± 0.51 N⋅m.kg-1 (range, 1.22-3.74 N⋅m.kg-1) and 1.04 ± 0.26 N⋅m.kg-1 (range, 0.41-1.50 N⋅m.kg-1) for flexors. For men, the normalized torque for extensors was 2.74 ± 0.58 N⋅m.kg-1 (range, 1.51-4.08 N⋅m.kg-1) and 1.24 ± 0.30 N⋅m.kg-1 (range, 0.64-2.05 N⋅m.kg-1) for flexors. This study provides absolute and normalized normative values of maximal isometric torque measured at 80° of knee flexion for extensors and flexors in a series of healthy trained subjects practicing activities at risk of anterior cruciate ligament rupture. The considerable level of interlimb asymmetry and the weak association between dominance and strength observed in uninjured subjects call into question the classical use of contralateral side as reference for injured patients. Patients with anterior cruciate ligament (ACL) injuries are the most represented subjects using isokinetic dynamometers in many sport medicine and rehabilitation departments. Clinicians need reference values to compare patients with ACL injuries with comparable healthy subjects. This study may provide this information.

Correlation analysis between biomechanical characteristics of taekwondo double roundhouse kick and effective scoring of electronic body protector.

Objective: To explore the inherent relationship between lower limb biomechanical indicators and effective scoring values of double roundhouse kick (DRK) by taekwondo athletes, and to find key biomechanical factors that trigger effective scoring. Methods: Using the DAEDO Protector and Scoring System (PSS) in conjunction with the Vicon optical motion capture system and Kistler 3D force plate, kinematic and dynamic indicators of the front kicking motion were obtained from 12 professional taekwondo athletes (18.00 ± 2.20years, 182.15 ± 8.62cm and 70.00 ± 14.82kg). The correlation between kinematics, dynamics, and scoring values was initially analyzed using bivariate linear correlation. Subsequently, based on the results of the linear correlation analysis, a stepwise regression analysis was performed to establish a stepwise regression equation. Results: The results reveal that during the First Hit, there is a significant positive correlation (r > 0, p < 0.05) between peak hip flexion angular velocity of the dominant leg, knee abduction angle, and peak foot horizontal plane linear velocity of the non-dominant leg with effective score. On the other hand, peak ankle flexion angular velocity of the non-dominant leg, peak foot sagittal plane linear velocity, peak hip abduction angle, and peak hip flexion angle of the dominant leg exhibit a significant negative correlation (r < 0, p < 0.05) with effective score. These correlations hold statistical significance (DW> 1.023). During the Second Hit, there is a significant positive correlation (r > 0, p < 0.05) between peak ankle internal rotation angular velocity of the dominant leg, foot coronal plane linear velocity, hip adduction angular velocity, and peak ankle internal rotation moment of the non-dominant leg with effective score. Conversely, peak hip flexion angle of the dominant leg shows a significant negative correlation (r < 0, p < 0.05) with effective score. All these variables have a statistically significant impact on effective score (DW > 1.023). Conclusion: Explosive power, body posture, adequate terminal velocity, and body rotation have an association with effective scoring of the electronic protector. The peak angular velocity of the ankle joint of the dominant leg and the peak linear velocity of the foot horizontal plane of the non-dominant leg significantly contribute to the effectiveness score of the electronic protector.

Exploring the Implications of Inter-Limb Asymmetries on Sprint, Agility, and Jump Performance in Young Highly-Trained Basketball Athletes: Is There a Relevant Threshold?

Background and Objectives: This study aimed to investigate the magnitude of vertical jump inter-limb asymmetries among young highly-trained basketball athletes and to analyze its impact on sport performance, specifically in sprints, agility, and vertical jumps. Materials and Methods: A unilateral countermovement jump (CMJ) was employed to determine Inter-limb Index Asymmetry (IAI) in 320 participants aged from 14 to 18 years, from the Valencia Basket youth academy. IAI was categorized into three groups: 0-9.9%, 10-14.9%, and >15%. The relationship between IAI and performance variables was analyzed through correlation studies (Pearson or Spearman's). The influence of IAI magnitude was assessed using ANOVA or Kruskal-Wallis analysis, with leg dominance as a covariable. SPSS Statistics version 26 was used for analysis. Results: Among all the participants, the mean IAI was 10.6%. Correlation studies revealed non-significant values (p < 0.05) between IAI and sport performance variables. The three IAI magnitude groups did not show statistically significant differences in sprint, agility, and jump outcomes. Leg dominance did not seem to influence performance outcomes, except for unilateral CMJ. Conclusions: The results obtained challenge the assumption that an IAI above 10% negatively affects sprint, agility, or jump performance in young basketball athletes. Notably, the magnitude of IAI did not influence sport performance parameters, suggesting that the 10-15% threshold from previous studies may not be applicable to this population. The study emphasizes the need to understand lower-limb asymmetries in the context of specific sport task performance, considering the potential evolution over time among affected young athletes.

FUNCTIONAL MOVEMENT SCREEN (FMSTM) AND BALANCE IN BODYBUILDERS DURING THE DEFINITION PERIOD

The functional movement and balance performances of bodybuilders and the relationship between them arouse curiosity in the definition period where intense restrictions are experienced. The aims of this study were to (a) determine functional movement screening (FMSTM) and balance performance in bodybuilders during the definition period and (b) examine the relationship between these tests. Twelve adult male bodybuilders voluntarily participated in the study. Participants performed flamingo balance test for static balance, upper &amp; lower quarter Y-balance test (YBT-LQ &amp; YBT-UQ) for dynamic balance, and FMS TM tests (deep squat, hurdle step, in-line lunge, shoulder mobility, active straight leg raise, trunk stability push-up, and rotary stability) for functional movement screening. There was a significant negative correlation between dominant leg static balance and rotary stability (r=-.832, p=.040) and a significant positive relationship between dynamic balance and rotary stability in dominant and non-dominant leg (dominant leg: r=.589, p=.044, non-dominant leg: r=.775, p=003). There was no significant relationship between YBT-UQ composite scores and FMSTM composite scores on both sides in bodybuilders during the definition period. As a result, the FMS TM score is quite low in bodybuilders during the definition period, and the increase in static and lower extremity dynamic balance performance may increase the rotary stability score. Bodybuilders are recommended to practice lower extremity static and dynamic balance exercises in addition to training during the definition period.

Functional and Psychological Preparedness of Athletes Post ACL Repair.

This study was conducted to see whether those who had anterior cruciate ligament (ACL) reconstructions on their dominant legs performed better than those who had them on their nondominant legs 1-10 years after the surgery. An examination of people who sustained injuries to their dominant (n = 25) and nondominant (n = 25) legs between 1 and 10 years after ACL repair was undertaken in a cross-sectional research with 50 people aged 20-38. Everyone takes the fear avoidance belief questionnaire for physical activity (FABQ-PA), the lower extremity functional scale (LEFS), and the anterior cruciate ligament return to sport after injury (ACL-RSI) survey. There was no statistically significant difference between the groups on the ACL-RSI, LEFS, and FABQ-PA (U = 254, P = 0.26; U = 314.4, P = 0.95; and U = 279.4, P = 0.53 correspondingly). Functional performance and patient mental health should be evaluated 1-10 years after ACL surgery. However, there is no correlation between which leg was the dominant one and the results. As a result, it has been shown that both dominant and nondominant leg injuries heal similarly over time. Future studies should examine additional variables that affect healing and return-to-sport results to improve rehabilitation and optimize long-term functional outcomes for individuals after ACL repair.

Effect of applied cadence in repeated sprint cycling on muscle characteristics

PurposeThis study aimed to investigate physiological responses, muscle–tendon unit properties of the quadriceps muscle, and mechanical performance after repeated sprint cycling at optimal and 70% of optimal cadence.MethodsTwenty recreational cyclists performed as first sprint performance cycling test and during subsequent sessions two repeated sprint cycling protocols at optimal and 70% of optimal cadence, in random order. The muscle–tendon unit outcome measures on the dominant leg included muscle thickness, fascicle length (Lf), pennation angle (θp), and stiffness for the rectus femoris (RF), vastus lateralis (VL), and vastus medialis muscle (VM) at baseline, immediately after repeated sprint cycling, and 1-h post-exercise.ResultsThe results showed an increase in muscle thickness and θp in RF, VL, and VM for both cadences from baseline to immediately after exercise. The Lf decreased in RF (both cadences), while stiffness decreased in RF, VL, and VM at optimal cadence, and in VL at 70% of optimal cadence from baseline to immediately after exercise.ConclusionThe present study revealed that the alterations in muscle characteristics were more marked after repeated sprint cycling at optimal cadence compared with a lower cadence most likely as a result of higher load on the muscle–tendon unit at optimal cadence.

Effect of gender, leg dominancy and body mass index on Y-balance performance among young healthy adults

This study investigated the influence of the sex, dominant leg and BMI on dynamic balance control of young adults (mean age; 20 ± 1.56) using the Y-balance test-lower quarter (YBT-LQ). This cross-sectional study included 218 participants (105 men and 103 women) who were recruited as a convenient sample of young, normal adults. The examination was implemented in one session, with three trials in each direction on each leg. The maximum reach distance of the three trials in each direction was used for statistical analysis. The reported reach distances were also normalized for each participant's leg length. Males' right leg values in the posteromedial (PM), posterolateral (PL), and composite directions were substantially longer than females' (p&lt;0.05), and no significant difference between both sexes in anterior (AT) direction (p&gt;0.05). In all directions, there were no significant differences between both sexes for the left leg (p&gt;0.05), and no significant differences between the right values of the dominant and non-dominant legs (p&gt;0.05). However, the left values of the non-dominant legs were longer than the dominant leg in directions (p&lt;0.05). The right leg values of the AT, PM, and composite values of the average BMI subjects was greater than the over-weight and obese subjects (p&lt;0.05), and the left leg values of the AT and composite values of the average BMI subjects was greater than over-weight and obese subjects (p&lt;0.05). Males have a longer right leg reach distance in the PM, PL directions, and composite value compared to females. The right leg dominant participants have longer reach distance of the left leg in all directions. When compared to over-weight and obese participants, average body weight subjects have bilaterally larger reach distance in the AT and composite directions.

The effect of body position, leg dominance, and automatic releasing mechanism on quadriceps muscle tone assessed by Pendulum Test in able-bodied persons.

<p>Quadriceps femoris muscle spasticity is commonly measured by the Wartenberg pendulum test. It is generally assumed that lower values of the number of swings of the leg and lower relaxation indexes are associated with higher muscle tone and more spasticity. Still, there is incoherence regarding the test&rsquo;s applications with various body positions and starting mechanisms. This study aims to investigate the influence of body position, leg dominance, and automatic leg-releasing mechanism on muscle tone measured by pendulum test in healthy population whose muscle tone is often compared to the spastic muscle tone of patients with neurologic disorders.&nbsp;</p>. <p>15 healthy adults (age: 19-32 years, 9 males, 6 females) participated in this study. A Zebris 3D ultrasound-based motion analysis system was used to record kinematic data during the pendulum test. The number of swings of the leg and the relaxation index were computed from the collected data. The pendulum test was completed in eight conditions: in supine and semi-supine positions on the dominant and non-dominant leg separately and with investigator-release and automata-release mechanisms. Paired t-tests and Wilcoxon test with the significance level of .05 were applied in comparison of pairs of the pendulum test condition.</p>. <p>1) Applying automata-release mode, in the non-dominant leg the number of swings (p=0.03) and the relaxation index (p&lt;0.001) were significantly higher in semi-supine than in supine position. 2) The non-dominant leg had significantly more swings than the dominant leg in both body positions with automata-release mode (p=0.009, p&lt;0.001). In investigator-release mode this occurred in supine position (p&lt;0.001). 3). Regarding the number of swings in investigator-release versus automata-release mode, no significant differences were found in any test condition, but the relaxation index showed significant difference for the non-dominant leg (p=0.01, p=0.009). 4) The values of the relaxation index didn&rsquo;t support in all test conditions the results what the number of swings provided about the muscle tone. In automata-release mode, the dominant leg has a lower number of swings and a higher relaxation index than the non-dominant leg.</p>. <p>The effect of body position on the quadriceps muscle tone can be assessed by applying the pendulum test with an automatic leg-releasing mechanism even when the application of conventional investigator-release mode does not show a significant effect. The pendulum test is more sensitive to assess spasticity with automatic-release than with investigator-release mode.&nbsp;</p>.