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Kinetic asymmetries during running in male youth

Rumpf MC, Cronin JB, Mohamad IN, Mohamad S, Oliver JL, Hughes MG

Phys Ther Sport, 2014 Feb;15(1):53-7.
PMID: 23850007 DOI: 10.1016/j.ptsp.2013.03.001

A possible injury risk factor is limb asymmetry, which may differ across maturation given the adult growth spurt. The aim of this study is to quantify the magnitude of asymmetry in a number of kinetic variables during a running task in male youth of different maturity status.

Matched MeSH terms: Leg/physiology*
Effect of pubertal developmental stages and lower limb kinetics during vertical jump task in Sepak Takraw sport

Leonard Joseph H, Roslizawati N, Safrusahar MY, Efri NM, Das S, Baharudin O, et al.

Clin Ter, 2009;160(5):403-7.
PMID: 19997687

Sepak Takraw is a sport which actively involves the lower limb. A cross sectional study was performed to investigate the lower limb kinetics (ground reaction force, flight time and contact time) involved during the vertical jumping and landing task between the early pubertal and late pubertal stages in National level Sepak Takraw athletes in Malaysia. Twenty athletes (8 pre pubertal and 12 late pubertal) with no previous history of any physical injuries were taken for the study. The kinetics data of the vertical jump task was calculated using a force platform 3-AMTI Biomechanics Force Platform. The Silicon ProCoach (Chart 5 software) was used to collect the ground reaction force signals, flight time and contact time. The results showed a non-significant decrease in peak ground reaction force in the post pubertal group as compared to the pre pubertal group (t(18)=0.659, p=0.518,CI(95)(-2.54, 4.86). Comparison of flight time between the two age groups showed a significant increase in the post pubertal group with mean and SD (0.7773 + or - 0.03) as compared to the pre pubertal group mean and SD (0.7296 + or - 0.05), which was statistically considered significant (p<0.05) (t(18)=-2.401, p<0.05,CI(95)(-0.089, -0.005). The findings from this study demonstrated that the flight time of the vertical jump task differed between the pre and post pubertal athletes with the post pubertal group having an improved ability in maintaining longer duration of flight phase.

Matched MeSH terms: Leg/physiology*
Aerial and Terrestrial Patterns: A Novel Approach to Analyzing Human Running

Gindre C, Lussiana T, Hebert-Losier K, Mourot L

Int J Sports Med, 2016 Jan;37(1):25-9.
PMID: 26509380 DOI: 10.1055/s-0035-1555931

Biomechanical parameters are often analyzed independently, although running gait is a dynamic system wherein changes in one parameter are likely to affect another. Accordingly, the Volodalen® method provides a model for classifying running patterns into 2 categories, aerial and terrestrial, using a global subjective rating scoring system. We aimed to validate the Volodalen® method by verifying whether the aerial and terrestrial patterns, defined subjectively by a running coach, were associated with distinct objectively-measured biomechanical parameters. The running patterns of 91 individuals were assessed subjectively using the Volodalen® method by an expert running coach during a 10-min running warm-up. Biomechanical parameters were measured objectively using the OptojumpNext® during a 50-m run performed at 3.3, 4.2, and 5 m·s(-1) and were compared between aerial- and terrestrial-classified subjects. Longer contact times and greater leg compression were observed in the terrestrial compared to the aerial runners. The aerial runners exhibited longer flight time, greater center of mass displacement, maximum vertical force and leg stiffness than the terrestrial ones. The subjective categorization of running patterns was associated with distinct objectively-quantified biomechanical parameters. Our results suggest that a subjective holistic assessment of running patterns provides insight into the biomechanics of running gaits of individuals.

Matched MeSH terms: Leg/physiology
The limits of stability and muscle activity in middle-aged adults during static and dynamic stance

Ku PX, Abu Osman NA, Wan Abas WAB

J Biomech, 2016 Dec 08;49(16):3943-3948.
PMID: 27865478 DOI: 10.1016/j.jbiomech.2016.11.006

Balance control plays an important role in maintaining daily activity. However, studies on postural control among middle-aged adults are scarce. This study aims (i) to examine directional control (DCL) and electromyography activity (EMG) for different stability levels, and (ii) to determine left-right asymmetry for DCL and muscle activity among sedentary middle-aged adults. Twenty healthy, middle-aged adults (10 males, 10 females; age=50.0±7.5yrs; body height: 1.61±0.10m; body mass: 70.0±14.5kg) participated in the study. EMG for left and right side of rectus femoris (RF), biceps femoris (BF), and medial gastrocnemius (MG) were recorded. Two-way repeated measures analysis of variance was used to assess the effect of dynamic level on DCL and EMG, whereas independent sample t-test was conducted to analyse the asymmetries of DCL and EMG for the left and right leg. When the dynamic tilt surface increased, DCL scores significantly decreased (except forward, forward-rightward, and backward-leftward direction) and only RF muscle indicated significant differences. Left-right asymmetry was found in BF and MG muscles. No significant gender difference was observed in DCL and EMG. These data demonstrated that increased dynamic tilt surface may increase the displacement of center of pressure of certain directions, and stimulate RF activity in dynamic stance among sedentary middle-aged adults. Further studies should be conducted to examine the dynamic stance and muscle activity of the lower limb in age-matched patient groups with balance abnormalities.

Matched MeSH terms: Leg/physiology
Biomechanical responses of thigh and lower leg during 10 consecutive soccer instep kicks

Amiri-Khorasani M, Abu Osman NA, Yusof A

J Strength Cond Res, 2011 Apr;25(4):1177-81.
PMID: 20838249 DOI: 10.1519/JSC.0b013e3181d6508c

This study investigated the number of trials necessary to obtain optimal biomechanical responses in 10 consecutive soccer instep kicks. The kicking motions of dominant legs were captured from 5 experienced and skilled adult male soccer players (height: 184.60 ± 4.49 cm; mass: 80 ± 4.24 kg; and age: 25.60 ± 1.14 years) using a 3D infrared high-speed camera at 200 Hz. Some of the important kinematics and kinetics parameters are maximum thigh angular velocity, maximum lower leg angular velocity, maximum of thigh moment, maximum lower leg moment at forward and impact phases, and finally maximum ball velocity after impact selected to be analyzed. There was a significant decrease of ball velocity between the first and the fifth kick and the subsequent kicks. Similarly, the lower leg angular velocity showed a significant decrease after the fifth kick and thereafter. Compared with the first kick, the thigh angular velocity has been shown to decrease after the sixth kick and thereafter, and the thigh moment result of the sixth kick was significantly lower when compared with the first kick. Moreover, the lower leg moment result of the fourth kick was significantly lower in comparison with the first kick. In conclusion, it seems that 5 consecutive kicks are adequate to achieve high kinematics and kinetics responses and selecting more than 5 kicks does not result in any high biomechanical responses for analysis.

Matched MeSH terms: Leg/physiology*
Fulltext The effects of comprehensive warm-up programs on proprioception, static and dynamic balance on male soccer players

Daneshjoo A, Mokhtar AH, Rahnama N, Yusof A

PLoS One, 2012;7(12):e51568.
PMID: 23251579 DOI: 10.1371/journal.pone.0051568

The study investigated the effects of FIFA 11+ and HarmoKnee, both being popular warm-up programs, on proprioception, and on the static and dynamic balance of professional male soccer players.

Matched MeSH terms: Leg/physiology
Fulltext Exoskeleton robot control for synchronous walking assistance in repetitive manual handling works based on dual unscented Kalman filter

Sado F, Yap HJ, Ghazilla RAR, Ahmad N

PLoS One, 2018;13(7):e0200193.
PMID: 30001415 DOI: 10.1371/journal.pone.0200193

Prolong walking is a notable risk factor for work-related lower-limb disorders (WRLLD) in industries such as agriculture, construction, service profession, healthcare and retail works. It is one of the common causes of lower limb fatigue or muscular exhaustion leading to poor balance and fall. Exoskeleton technology is seen as a modern strategy to assist worker's in these professions to minimize or eliminate the risk of WRLLDs. Exoskeleton has potentials to benefit workers in prolong walking (amongst others) by augmenting their strength, increasing their endurance, and minimizing high muscular activation, resulting in overall work efficiency and productivity. Controlling exoskeleton to achieve this purpose for able-bodied personnel without impeding their natural movement is, however, challenging. In this study, we propose a control strategy that integrates a Dual Unscented Kalman Filter (DUKF) for trajectory generation/prediction of the spatio-temporal features of human walking (i.e. joint position, and velocity, and acceleration) and an impedance cum supervisory controller to enable the exoskeleton to follow this trajectory to synchronize with the human walking. Experiment is conducted with four subjects carrying a load and walking at their normal speed- a typical scenario in industries. EMG signals taken at two muscles: Right Vastus Intermedius (on the thigh) and Right Gastrocnemius (on the calf) indicated reduction in muscular activation during the experiment. The results also show the ability of the control system to predict spatio-temporal features of the pilots' walking and to enable the exoskeleton to move in concert with the pilot.

Matched MeSH terms: Leg/physiology
Effect of low-cost resistance training on lower-limb strength and balance in institutionalized seniors

Motalebi SA, Cheong LS, Iranagh JA, Mohammadi F

Exp Aging Res, 2018 1 18;44(1):48-61.
PMID: 29336735 DOI: 10.1080/0361073X.2017.1398810

Background/Study Context: Given the rapid increase in the aging population worldwide, fall prevention is of utmost importance. It is essential to establish an efficient, simple, safe, and low-cost intervention method for reducing the risk of falls. This study examined the effect of 12 weeks of progressive elastic resistance training on lower-limb muscle strength and balance in seniors living in the Rumah Seri Kenangan, social welfare home in Cheras, Malaysia.
METHODS: A total of 51 subjects qualified to take part in this quasi-experimental study. They were assigned to either the resistance exercise group (n = 26) or control group (n = 25). The mean age of the 45 participants who completed the program was 70.7 (SD = 6.6). The exercise group met twice per week and performing one to three sets of 8 to 10 repetitions for each of nine lower-limb elastic resistance exercises. All exercises were conducted at low to moderate intensities in sitting or standing positions. The subjects were tested at baseline and 6 and 12 weeks into the program.
RESULTS: The results showed statistically significant improvements in lower-limb muscle strength as measured by five times sit-to-stand test (%Δ = 22.6) and dynamic balance quantified by the timed up-and-go test (%Δ = 18.7), four-square step test (%Δ = 14.67), and step test for the right (%Δ = 18.36) and left (%Δ = 18.80) legs. No significant changes were observed in static balance as measured using the tandem stand test (%Δ = 3.25), and one-leg stand test with eyes opened (%Δ = 9.58) and eyes closed (%Δ = -0.61) after completion of the program.
CONCLUSION: The findings support the feasibility and efficacy of a simple and inexpensive resistance training program to improve lower-limb muscle strength and dynamic balance among the institutionalized older adults.

Matched MeSH terms: Leg/physiology
Enhanced performance with elastic resistance during the eccentric phase of a countermovement jump

Aboodarda SJ, Yusof A, Abu Osman NA, Thompson MW, Mokhtar AH

Int J Sports Physiol Perform, 2013 Mar;8(2):181-7.
PMID: 23428490

To identify the effect of additional elastic force on the kinetic and kinematic characteristics, as well as the magnitude of leg stiffness, during the performance of accentuated countermovement jumps (CMJs).

Matched MeSH terms: Leg/physiology*
Fulltext Muscle oxygenation during hybrid arm and functional electrical stimulation-evoked leg cycling after spinal cord injury

Hasnan N, Mohamad Saadon NS, Hamzaid NA, Teoh MX, Ahmadi S, Davis GM

Medicine (Baltimore), 2018 Oct;97(43):e12922.
PMID: 30412097 DOI: 10.1097/MD.0000000000012922

This study compared muscle oxygenation (StO2) during arm cranking (ACE), functional electrical stimulation-evoked leg cycling (FES-LCE), and hybrid (ACE+FES-LCE) exercise in spinal cord injury individuals. Eight subjects with C7-T12 lesions performed exercises at 3 submaximal intensities. StO2 was measured during rest and exercise at 40%, 60%, and 80% of subjects' oxygen uptake (VO2) peak using near-infrared spectroscopy. StO2 of ACE showed a decrease whereas in ACE+FES-LCE, the arm muscles demonstrated increasing StO2 from rest in all of VO2) peak respectively. StO2 of FES-LCE displayed a decrease at 40% VO2 peak and steady increase for 60% and 80%, whereas ACE+FES-LCE revealed a steady increase from rest at all VO2 peak. ACE+FES-LCE elicited greater StO2 in both limbs which suggested that during this exercise, upper- and lower-limb muscles have higher blood flow and improved oxygenation compared to ACE or FES-LCE performed alone.

Matched MeSH terms: Leg/physiology*
Fulltext Blood Flow-restricted Exercise Does Not Induce a Cross-Transfer of Effect: A Randomized Controlled Trial

Ampomah K, Amano S, Wages NP, Volz L, Clift R, Ludin AFM, et al.

Med Sci Sports Exerc, 2019 Sep;51(9):1817-1827.
PMID: 30913160 DOI: 10.1249/MSS.0000000000001984

PURPOSE: The goal of this trial was to determine whether low-load blood flow-restricted (BFR) exercise of appendicular muscles induces a cross-transfer of effect to the trunk extensor (TE) muscles, such that low-load TE exercise would enhance TE size and function to a greater extent than standard low-load exercise in people with recurrent low back pain (LBP). We also investigated the direct effects of BFR exercise in the appendicular muscles.
METHODS: Thirty-two adults with recurrent, nonspecific LBP were randomized into two groups: Appendicular BFR exercise (BFR exercise) or control exercise (CON exercise). All participants trained (two times per week) for 10 wk, with a 12-wk follow-up. Participants performed three sets of leg extension (LE), plantar flexion (PF), and elbow flexion (EF) exercises followed by low-load TE exercise without BFR. Outcome measures included magnetic resonance imaging-derived muscle size (quadriceps and TE), strength (LE, PF, EF, and TE), and endurance (LE and TE).
RESULTS: There was no evidence for a cross-transfer of effect to the TE. There was also no statistically significant enhancement of limb skeletal muscle size or function of BFR relative to CON exercise at any time point; though, moderate effect sizes for BFR exercise were observed for enhanced muscle size and strength in the leg extensors.
CONCLUSIONS: Low-load BFR exercise of the appendicular muscles did not result in a cross-transfer of effect to the TE musculature. There was also no significant benefit of low-load BFR exercise on the appendicular muscle size and function, suggesting no benefit from low-load BFR exercise in adults with recurrent, nonspecific LBP.

Matched MeSH terms: Leg/physiology