Comparison of crossover and jab step start techniques in sprinting for football and handball players

There are two techniques for a lateral sprint start: crossover (CS) and jab step (JS) starts. This study aimed to elucidate the difference in the CS and JS starts in terms of sprint performance and leg kinetics in athletes from ball-and-goal type sports (e.g. soccer and handball). Nineteen male athletes performed CS and JS starts, during which their motion and the force they applied to the ground were simultaneously recorded using a motion-capture system and two force platforms. The results showed that, although 5-m time via video analysis did not differ between CS and JS starts, forward velocity of centre of gravity (CG) and normalised average horizontal external power were greater for the JS start than the CS start. From waveform analysis, greater positive joint power in the sagittal plane leading to greater positive work in the JS start were found in the first three quarters of the push-off phase for rear hip extension and in the subsequent push-off phase for rear ankle plantar flexion. In conclusion, the results suggest that the JS start is superior to the CS start for start quickness, though the gains in the start did not appear to transfer to the 5-m performance. Moreover, greater positive joint power in the first three quarters of the push-off phase for the rear hip extension and in the subsequent push-off phase for the rear ankle plantar flexion were considered to be important contributing factors to the better performance of the JS start.

Does Gait with an Ankle Foot Orthosis Improve or Compromise Minimum Foot Clearance?

The purpose of this study was to investigate if the use of an ankle foot orthosis in passive mode (without actuation) could modify minimum foot clearance, and if there are any compensatory mechanisms to enable these changes during treadmill gait at a constant speed. Eight participants walked on an instrumented treadmill without and with an ankle foot orthosis on the dominant limb at speeds of 0.8, 1.2, and 1.6 km/h. For each gait cycle, the minimum foot clearance and some gait linear kinematic parameters were calculated by an inertial motion capture system. Additionally, maximum hip and knee flexion and maximum ankle plantar flexion were calculated. There were no significant differences in the minimum foot clearance between gait conditions and lower limbs. However, differences were found in the swing, stance and step times between gait conditions, as well as between limbs during gait with orthosis (p < 0.05). An increase in hip flexion during gait with orthosis was observed for all speeds, and different ankle ranges of motion were observed according to speed (p < 0.05). Thus, the use of an ankle foot orthosis in passive mode does not significantly hinder minimum foot clearance, but can change gait linear and angular parameters in non-pathological individuals.

Assessment of Functional End Ranges of Lower Limb Joints in Positions Commonly Used for ADLs in India

Background: In many countries of Asian continent, floor sitting is preferred instead of chair supported sitting. Indian population differs noticeably in its cultural practice and daily tasks which involves squatting and cross-legged sitting on the ground. Aim: The purpose of the study was to assess the functional end-ranges of the hip, knee and ankle joints in healthy Indian subjects in positions commonly used for ADLs in India which includes squatting and cross-legged sitting. Methods: 66 healthy subjects were recruited from rural and urban populations with age range 30-50 years. Joint ROM of the lower extremities was measured using Universal Goniometer. All the subjects were asked to acquire squat and cross legged positions which were graded. Results: Our results finding showed that the subjects in cross leg sitting grade 2 (independent CLS) had hip flexion ranges ≥1150, hip abduction ≥ 410, hip external rotation ≥ 420, ankle plantar flexion ≥ 460, p<0.005. For squatting, grade 2 (independent squat) had hip flexion ranges ≥ 1130,p>0.005, Knee flexion ≥1200, p>0.005 and ankle dorsiflexion ≥150, p<0.005. Conclusion: From the results, it is suggested that squatting and cross-leg sitting multiple times a day can prevent the early closer of end ranges of the lower limbs.

The effect of ankle flexibility on the relationship between knee isokinetic strength and the speed of underwater dolphin kicks in male competitive swimmers

BACKGROUND: Lower-extremity muscle strength and ankle flexibility play key roles in underwater swimming movements. OBJECTIVES: To investigate the relationship between knee isokinetic strength and the speed of underwater dolphin kicks (UDK-S) in competitive male swimmers and identify whether ankle flexibility affects the association between knee isokinetic strength and UDK-S. METHODS: Fifty-two highly trained male swimmers participated in this study. The speed at which the participants travelled 15 m performing UDKs was calculated as UDK-S. Knee flexor and extensor concentric isokinetic strength at fast (240∘/s) and slow (60∘/s) velocities and ankle flexibility were evaluated. Bayesian framework analysis was conducted to examine the relationship between these variables and determine whether this relationship is influenced by ankle flexibility. RESULTS: There was strong-to-extremely strong evidence (Bayes factor = 24.4 to 198.3) that knee extensor (60∘/s) and knee flexor (60∘/s and 240∘/s) strength are positively and generally moderately correlated with UDK-S. Ankle plantar flexion flexibility was identified to be a moderator between knee extensor strength (60∘/s) and UDK-S. CONCLUSIONS: Knee extensor and knee flexor strength were significantly correlated with UDK-S, and the relationship between knee muscle strength and UDK-S was influenced by ankle plantar flexion flexibility in male competitive swimmers.

Heel Rise and Non–Weight-Bearing Ankle Plantar-Flexion Tasks to Assess Foot and Ankle Function in People With Diabetes Mellitus and Peripheral Neuropathy

Objective To examine the effects of diabetes mellitus and peripheral neuropathy (DMPN), limited joint mobility, and weight bearing on foot and ankle sagittal movements; and characterize the foot and ankle position during heel rise. Methods Sixty people with DMPN and 22 controls participated. Primary outcomes were foot (forefoot on hindfoot) and ankle (hindfoot on shank) plantar-flexion/dorsiflexion angle during three tasks: unilateral heel rise, bilateral heel rise, and non–weight-bearing ankle plantar flexion. A repeated measures analysis of variance and Fisher exact test were used. Results Main effects of task and group were significant, but not the interaction in both foot and ankle plantar flexion. Foot and ankle plantar flexion were less in people with DMPN compared to controls in all tasks. Both DMPN and control groups had significantly less foot and ankle plantar flexion with greater weight bearing, however, the linear trend across tasks was similar between groups. The DMPN group had a greater percentage of individuals in foot and/or ankle dorsiflexion at peak unilateral heel rise compared to controls, but the foot and ankle position was similar at peak bilateral heel rise between DMPN and control groups. Conclusions Foot and ankle plantar flexion is less in people with DMPN. Less plantar flexion in non–weight bearing suggests that people with DMPN have limited joint mobility. However, peak unilateral and bilateral heel rise is less than the available plantar-flexion range of motion measured in non–weight bearing indicating that limited joint mobility does not limit heel rise performance. A higher frequency of people with DMPN are in foot and ankle dorsiflexion at peak unilateral heel rise compared to controls, but the position improved with lower weight bearing. Impact Proper resistance should be considered with physical therapist interventions utilizing heel rise because foot and ankle plantar-flexion position could be improved by reducing the amount of weight bearing.

Protein Intake and Physical Performance Following Long-Term Stay on the International Space Station

INTRODUCTION: Exposure to microgravity reduces muscle mass, volume, and performance. The ingestion of protein, especially combined with carbohydrate intake and exercise after ingestion, improves net muscle protein synthesis and increases muscle mass. However, there are few studies on this relationship during and after a long-term spaceflight. The objective of this study was to investigate the influence of protein and the combined effects of carbohydrate intake on muscle performance following long-term spaceflight.METHODS: This study is a retrospective cohort study involving secondary analysis of data stored in the NASA Lifetime Surveillance of Astronaut Health Repository. Multivariable analysis was performed to evaluate the impact of protein intake on physical performance by considering covariates potentially associated with each model.RESULTS: After adjusting for sex, age, flight week, energy intake, and preflight physical performance, protein intake was found to be significantly associated with concentric measurements for knee extension ( 51.66), ankle plantar flexion ( 32.86), and eccentric measurements for ankle plantar flexion ( 79.85) at 5 d after landing. Significant associations remained after controlling for exercise effect. No significant interaction between protein and carbohydrate intake was observed in either model.DISCUSSION: Protein intake during spaceflight was related to physical performance for knee extension and ankle plantar flexion, even after taking exercise effect into consideration. However, protein and carbohydrate intake provided no synergetic benefit. This suggests that high protein intake, about twice the current average intake, may serve as a countermeasure to offset the negative effects of long-duration spaceflights.Nozawa Y, Wagatsuma Y. Protein intake and physical performance following long-term stay on the International Space Station. Aerosp Med Hum Perform. 2021; 92(3):153159.

Acute Effects of Tissue Flossing on Ankle Range of Motion and Tensiomyography Parameters

Context: Recently, a few papers have suggested that tissue flossing (TF) acutely improves range of motion (ROM) and neuromuscular performance. However, the effects of TF on muscle contractile properties are yet to be defined. Objective: To investigate the acute effects of TF on ankle ROM and associated muscle gastrocnemius medialis displacement and contraction time assessed with tensiomyography. Design: Crossover design in a single session. Setting: University laboratory. Participants: Thirty recreationally trained volunteers (age 23.00 [4.51] y). Intervention: Active ankle plantar flexion and dorsiflexion were performed for the duration of 2 minutes (3 sets, 2-min rest between sets), while a randomly selected ankle was wrapped using TF elastic band (BAND) and the other ankle served as a control condition (CON). Main Outcome Measures: Participants performed an active ankle plantar flexion and dorsiflexion ROM test and muscle gastrocnemius medialis tensiomyography displacement and contraction time measurement pre, 5, 15, 30, and 45 minutes after the floss band application. Results: There were no statistically significant differences between BAND and CON conditions (active ankle plantar flexion ROM: P = .09; active ankle dorsiflexion ROM: P = .85); however, all ROM measurements were associated with medium or large effect sizes in favor of BAND compared with CON. No significant changes were observed in the tensiomyography parameters. Conclusions: The results of this study suggest that TF applied to the ankle is a valid method to increase ROM and at the same time maintaining muscular stiffness.

Effect of mobilization on ankle mobility and balance performance in diabetic patients

Introduction and Aim: Diabetic Cheiroarthropathy is defined as the condition of restriction joint mobility due to pseudo-sclerodermatous hand, the fibrosis of the elastin connective tissues over the skin. It limits joint mobility especially around Tibia fibular mobility that are interrelated with the flexibility of ankle motion that results in the balance disorder in diabetic population. The aim of the study was to determine the effects of the tibia fibular mobilization technique on ankle joint in diabetes mellitus patients. Materials and Methods: 60 diabetic subjects were randomly assigned into experimental group and control, in which experimental group received Tibia fibular mobilization technique and conventional treatment whereas control group received only conventional treatment 1 time a week for 3 weeks. Results: There is no significant difference in Ankle dorsi flexion range of motion in both extremities but there is significant difference in ankle plantar flexion range of motion in both extremities and functional reach test in both extremities. Conclusion: There is a significant difference in the ankle plantar flexion range of motion and functional reach test, Hence, mobilization of Tibiofibular joint will be beneficial in improving the ankle range of motion and balance factor in the diabetic population.