Displaying publications 1 - 20 of 116 in total

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  1. Daneshjoo A, Abu Osman NA, Sahebozamani M, Yusof A
    PLoS One, 2015;10(11):e0143323.
    PMID: 26599336 DOI: 10.1371/journal.pone.0143323
    PURPOSE: Running at high speed and sudden change in direction or activity stresses the knee. Surprisingly, not many studies have investigated the effects of sprinting on knee's kinetics and kinematics of soccer players. Hence, this study is aimed to investigate indices of injury risk factors of jumping-landing maneuvers performed immediately after sprinting in male soccer players.

    METHODS: Twenty-three collegiate male soccer players (22.1±1.7 years) were tested in four conditions; vertical jump (VJ), vertical jump immediately after slow running (VJSR), vertical jump immediately after sprinting (VJFR) and double horizontal jump immediately after sprinting (HJFR). The kinematics and kinetics data were measured using Vicon motion analyzer (100Hz) and two Kistler force platforms (1000Hz), respectively.

    RESULTS: For knee flexion joint angle, (p = 0.014, η = 0.15) and knee valgus moment (p = 0.001, η = 0.71) differences between condition in the landing phase were found. For knee valgus joint angle, a main effect between legs in the jumping phase was found (p = 0.006, η = 0.31), which suggests bilateral deficit existed between the right and left lower limbs.

    CONCLUSION: In brief, the important findings were greater knee valgus moment and less knee flexion joint angle proceeding sprint (HJFR & VJFR) rather than no sprint condition (VJ) present an increased risk for knee injuries. These results seem to suggest that running and sudden subsequent jumping-landing activity experienced during playing soccer may negatively change the knee valgus moment. Thus, sprinting preceding a jump task may increase knee risk factors such as moment and knee flexion joint angle.

  2. Amiri-Khorasani M, Abu Osman NA, Yusof A
    J Strength Cond Res, 2011 Jun;25(6):1647-52.
    PMID: 21358428 DOI: 10.1519/JSC.0b013e3181db9f41
    The purpose of this study was to examine the effects of static and dynamic stretching within a pre-exercise warm-up on hip dynamic range of motion (DROM) during instep kicking in professional soccer players. The kicking motions of dominant legs were captured from 18 professional adult male soccer players (height: 180.38 ± 7.34 cm; mass: 69.77 ± 9.73 kg; age: 19.22 ± 1.83 years) using 4 3-dimensional digital video cameras at 50 Hz. Hip DROM at backward, forward, and follow-through phases (instep kick phases) after different warm-up protocols consisting of static, dynamic, and no-stretching on 3 nonconsecutive test days were captured for analysis. During the backswing phase, there was no difference in DROM after the dynamic stretching compared with the static stretching relative to the no-stretching method. There was a significant difference in DROM after the dynamic stretching compared with the static stretching relative to the no-stretching method during (a) the forward phase with p < 0.03, (b) the follow-through phase with p < 0.01, and (c) all phases with p < 0.01. We concluded that professional soccer players can perform a higher DROM of the hip joint during the instep kick after dynamic stretching incorporated in warm-ups, hence increasing the chances of scoring and injury prevention during soccer games.
  3. 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.
  4. Gholizadeh H, Abu Osman NA, Eshraghi A, Ali S, Yahyavi ES
    Arch Phys Med Rehabil, 2013 Aug;94(8):1584-9.
    PMID: 23262380 DOI: 10.1016/j.apmr.2012.12.007
    To compare a seal-in liner with the common suction socket with regards to patient satisfaction and problems experienced with the prosthesis.
  5. Abu Osman NA, Spence WD, Solomonidis SE, Paul JP, Weir AM
    Med Eng Phys, 2010 Sep;32(7):760-5.
    PMID: 20678997 DOI: 10.1016/j.medengphy.2010.04.020
    The purpose of this investigation was to vary the load on the patellar tendon bar and to study the subsequent effect this has on the pattern of the pressure distribution at the stump-socket interface. Ten male subjects from the Southern General Hospital in Glasgow, UK participated in this study. Measuring systems utilising strain gauge and electrohydraulic technologies were designed, developed and constructed to enable pressure measurements to be conducted. One transducer, the patellar tendon (PT) transducer, was attached to the patellar tendon bar of the socket such that the patellar tendon bar was capable of being translated by +/-10 mm towards or away from the tendon. The results of this study showed that the position of the patellar tendon bar had no significant effect on the pressure distribution around the socket indicating that it is an unnecessary feature, which, we propose, may be eliminated during manufacture of a trans-tibial socket.
  6. Abu Osman NA, Gholizadeh H, Eshraghi A, Wan Abas WAB
    Prosthet Orthot Int, 2017 Oct;41(5):476-483.
    PMID: 28946824 DOI: 10.1177/0309364616670396
    OBJECTIVES: This study aimed to evaluate and compare a newly designed suspension system with a common suspension in the market.

    STUDY DESIGN: Prospective study.

    METHODS: Looped liners with hook fastener and Iceross Dermo Liner with pin/lock system were mechanically tested using a tensile testing machine in terms of system safety. A total of 10 transtibial amputees participated in this study and were asked to use these two different suspension systems. The pistoning was measured between the liner and socket through a photographic method. Three static axial loading conditions were implemented, namely, 30, 60, and 90 N. Furthermore, subjective feedback was obtained.

    RESULTS: Tensile test results showed that both systems could safely tolerate the load applied to the prosthesis during ambulation. Clinical evaluation confirmed extremely low pistoning in both systems (i.e. less than 0.4 cm after adding 90 N traction load to the prosthesis). Subjective feedback also showed satisfaction with both systems. However, less traction at the end of the residual limb was reported while looped liner was used.

    CONCLUSION: The looped liner with hook fastener is safe and a good alternative for individuals with transtibial amputation as this system could solve some problems with the current systems. Clinical relevance The looped liner and hook fastener were shown to be good alternative suspension for people with lower limb amputation especially those who have difficulty to use and align the pin/lock systems. This system could safely tolerate centrifugal forces applied to the prosthesis during normal and fast walking.

  7. 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.
  8. Pirouzi G, Abu Osman NA, Eshraghi A, Ali S, Gholizadeh H, Wan Abas WA
    ScientificWorldJournal, 2014;2014:849073.
    PMID: 25197716 DOI: 10.1155/2014/849073
    Socket is an important part of every prosthetic limb as an interface between the residual limb and prosthetic components. Biomechanics of socket-residual limb interface, especially the pressure and force distribution, have effect on patient satisfaction and function. This paper aimed to review and evaluate studies conducted in the last decades on the design of socket, in-socket interface pressure measurement, and socket biomechanics. Literature was searched to find related keywords with transtibial amputation, socket-residual limb interface, socket measurement, socket design, modeling, computational modeling, and suspension system. In accordance with the selection criteria, 19 articles were selected for further analysis. It was revealed that pressure and stress have been studied in the last decaeds, but quantitative evaluations remain inapplicable in clinical settings. This study also illustrates prevailing systems, which may facilitate improvements in socket design for improved quality of life for individuals ambulating with transtibial prosthesis. It is hoped that the review will better facilitate the understanding and determine the clinical relevance of quantitative evaluations.
  9. Khalaj N, Abu Osman NA, Mokhtar AH, Mehdikhani M, Wan Abas WA
    PLoS One, 2014;9(3):e92270.
    PMID: 24642715 DOI: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC39584
    Balance is essential for mobility and performing activities of daily living. People with knee osteoarthritis display impairment in knee joint proprioception. Thus, the aim of this study was to evaluate balance and risk of fall in individuals with bilateral mild and moderate knee osteoarthritis. Sixty subjects aged between 50 and 70 years volunteered in this study. They were categorized into three groups which were healthy (n = 20), mild (n = 20) and moderate (n = 20) bilateral knee osteoarthritis groups. Dynamic and static balance and risk of fall were assessed using Biodex Stability System. In addition, Timed Up and Go test was used as a clinical test for balance. Results of this study illustrated that there were significant differences in balance (dynamic and static) and risk of fall between three groups. In addition, the main (most significant) difference was found to be between healthy group and moderate group. Furthermore, on clinical scoring of balance, the "Timed Up and Go" test, all three groups showed significant difference. In conclusion, bilateral knee osteoarthritis impaired the balance and increased the risk of fall, particularly in people with moderate knee osteoarthritis.
  10. Eshraghi A, Abu Osman NA, Karimi M, Gholizadeh H, Soodmand E, Wan Abas WA
    PLoS One, 2014;9(5):e96988.
    PMID: 24865351 DOI: 10.1371/journal.pone.0096988
    Prosthetic suspension system is an important component of lower limb prostheses. Suspension efficiency can be best evaluated during one of the vital activities of daily living, i.e. walking. A new magnetic prosthetic suspension system has been developed, but its effects on gait biomechanics have not been studied. This study aimed to explore the effect of suspension type on kinetic and kinematic gait parameters during level walking with the new suspension system as well as two other commonly used systems (the Seal-In and pin/lock). Thirteen persons with transtibial amputation participated in this study. A Vicon motion system (six cameras, two force platforms) was utilized to obtain gait kinetic and kinematic variables, as well as pistoning within the prosthetic socket. The gait deviation index was also calculated based on the kinematic data. The findings indicated significant difference in the pistoning values among the three suspension systems. The Seal-In system resulted in the least pistoning compared with the other two systems. Several kinetic and kinematic variables were also affected by the suspension type. The ground reaction force data showed that lower load was applied to the limb joints with the magnetic suspension system compared with the pin/lock suspension. The gait deviation index showed significant deviation from the normal with all the systems, but the systems did not differ significantly. Main significant effects of the suspension type were seen in the GRF (vertical and fore-aft), knee and ankle angles. The new magnetic suspension system showed comparable effects in the remaining kinetic and kinematic gait parameters to the other studied systems. This study may have implications on the selection of suspension systems for transtibial prostheses. Trial registration: Iranian Registry of Clinical Trials IRCT2013061813706N1.
  11. Arifin N, Abu Osman NA, Ali S, Wan Abas WA
    Biomed Eng Online, 2014;13(1):23.
    PMID: 24597518 DOI: 10.1186/1475-925X-13-23
    Achieving independent upright posture has known to be one of the main goals in rehabilitation following lower limb amputation. The purpose of this study was to compare postural steadiness of below knee amputees with visual alterations while wearing three different prosthetic feet.
  12. Khalaj N, Abu Osman NA, Mokhtar AH, Mehdikhani M, Wan Abas WA
    Proc Inst Mech Eng H, 2014 Feb;228(2):190-9.
    PMID: 24458100 DOI: 10.1177/0954411914521155
    The knee adduction moment represents the medial knee joint load, and greater value is associated with higher load. In people with knee osteoarthritis, it is important to apply proper treatment with the least side effects to reduce knee adduction moment and, consequently, reduce medial knee joint load. This reduction may slow the progression of knee osteoarthritis. The research team performed a literature search of electronic databases. The search keywords were as follows: knee osteoarthritis, knee adduction moment, exercise program, exercise therapy, gait retraining, gait modification and knee joint loading. In total, 12 studies were selected, according to the selection criteria. Findings from previous studies illustrated that exercise and gait retraining programs could alter knee adduction moment in people with knee osteoarthritis. These treatments are noninvasive and nonpharmacological which so far have no or few side effects, as well as being low cost. The results of this review revealed that gait retraining programs were helpful in reducing the knee adduction moment. In contrast, not all the exercise programs were beneficial in reducing knee adduction moment. Future studies are needed to indicate best clinical exercise and gait retraining programs, which are most effective in reducing knee adduction moment in people with knee osteoarthritis.
    Study design: systematic review
  13. Gholizadeh H, Abu Osman NA, Eshraghi A, Ali S, Arifin N, Wan Abas WA
    Biomed Eng Online, 2014;13:1.
    PMID: 24410918 DOI: 10.1186/1475-925X-13-1
    Good prosthetic suspension system secures the residual limb inside the prosthetic socket and enables easy donning and doffing. This study aimed to introduce, evaluate and compare a newly designed prosthetic suspension system (HOLO) with the current suspension systems (suction, pin/lock and magnetic systems).
  14. Chandrasekhar A, Abu Osman NA, Tham LK, Lim KS, Wan Abas WA
    PLoS One, 2013;8(11):e80799.
    PMID: 24260483 DOI: 10.1371/journal.pone.0080799
    BACKGROUND: A clinical parameter commonly used to assess the neurological status of an individual is the tendon reflex response. However, the clinical method of evaluation often leads to subjective conclusions that may differ between examiners. Moreover, attempts to quantify the reflex response, especially in older age groups, have produced inconsistent results. This study aims to examine the influence of age on the magnitude of the patellar tendon reflex response.

    METHODOLOGY/PRINCIPAL FINDINGS: This study was conducted using the motion analysis technique with the reflex responses measured in terms of knee angles. Forty healthy subjects were selected and categorized into three different age groups. Patellar reflexes were elicited from both the left and right patellar tendons of each subject at three different tapping angles and using the Jendrassik maneuver. The findings suggested that age has a significant effect on the magnitude of the reflex response. An angle of 45° may be the ideal tapping angle at which the reflex can be elicited to detect age-related differences in reflex response. The reflex responses were also not influenced by gender and were observed to be fairly symmetrical.

    CONCLUSIONS/SIGNIFICANCE: Neurologically normal individuals will experience an age-dependent decline in patellar reflex response.

  15. Ku PX, Abu Osman NA, Wan Abas WA
    Gait Posture, 2014 Feb;39(2):672-82.
    PMID: 24331296 DOI: 10.1016/j.gaitpost.2013.07.006
    Postural control has been widely evaluated for the normal population and different groups over the past 20 years. Numerous studies have investigated postural control in quiet standing posture among amputees. However, a comprehensive analysis is lacking on the possible contributing factors to balance. The present systematic review highlights the current findings on variables that contribute to balance instability for lower extremity amputees. The search strategy was performed on PubMed, Web of Science, Medline, Scopus, and CINAHL and then followed by additional manual searching via reference lists in the reviewed articles. The quality of the articles was evaluated using a methodological quality assessment tool. This review included and evaluated a total of 23 full-text articles. Despite the inconsistencies in the methodological design of the studies, all articles scored above the acceptable level in terms of quality. A majority of the studies revealed that lower extremity amputees have increased postural sway in the standing posture. Asymmetry in body weight, which is mainly distributed in the non-amputated leg, was described. Aside from the centre of pressure in postural control, sensory inputs may be a related topic for investigation in view of evidence on their contribution, particularly visual input. Other balance-related factors, such as stump length and patients' confidence level, were also neglected. Further research requires examination on the potential factors that affect postural control as the information of standing postural is still limited.
  16. Ali S, Abu Osman NA, Eshraghi A, Gholizadeh H, Abd Razak NA, Wan Abas WA
    Clin Biomech (Bristol, Avon), 2013 Nov-Dec;28(9-10):994-9.
    PMID: 24161521 DOI: 10.1016/j.clinbiomech.2013.09.004
    Transtibial amputees encounter stairs and steps during their daily activities. The excessive pressure between residual limb/socket may reduce the walking capability of transtibial prosthetic users during ascent and descent on stairs. The purposes of the research were to evaluate the interface pressure between Dermo (shuttle lock) and Seal-In X5 (prosthetic valve) interface systems during stair ascent and descent, and to determine their satisfaction effects on users.
  17. Arifin N, Abu Osman NA, Wan Abas WA
    J Appl Biomech, 2014 Apr;30(2):300-4.
    PMID: 23878204 DOI: 10.1123/jab.2013-0130
    The measurements of postural balance often involve measurement error, which affects the analysis and interpretation of the outcomes. In most of the existing clinical rehabilitation research, the ability to produce reliable measures is a prerequisite for an accurate assessment of an intervention after a period of time. Although clinical balance assessment has been performed in previous study, none has determined the intrarater test-retest reliability of static and dynamic stability indexes during dominant single stance. In this study, one rater examined 20 healthy university students (female=12, male=8) in two sessions separated by 7 day intervals. Three stability indexes--the overall stability index (OSI), anterior/posterior stability index (APSI), and medial/ lateral stability index (MLSI) in static and dynamic conditions--were measured during single dominant stance. Intraclass correlation coefficient (ICC), standard error measurement (SEM) and 95% confidence interval (95% CI) were calculated. Test-retest ICCs for OSI, APSI, and MLSI were 0.85, 0.78, and 0.84 during static condition and were 0.77, 0.77, and 0.65 during dynamic condition, respectively. We concluded that the postural stability assessment using Biodex stability system demonstrates good-to-excellent test-retest reliability over a 1 week time interval.
  18. Ku PX, Abu Osman NA, Yusof A, Wan Abas WA
    J Biomech, 2012 Jun 1;45(9):1638-42.
    PMID: 22507349 DOI: 10.1016/j.jbiomech.2012.03.029
    Postural stability is crucial in maintaining body balance during quiet standing, locomotion, and any activities that require a high degree of balance performance, such as participating in sports and dancing. Research has shown that there is a relationship between stability and body mass. The aims of this study were to examine the impact that two variables had on static postural control: body mass index (BMI) and gender. Eighty healthy young adults (age=21.7±1.8 yr; height=1.65±0.09 m; mass=67.5±19.0 kg) participated in the study and the static postural control was assessed using the Biodex Balance System, with a 20 Hz sampling rate in the bipedic stance (BLS) and unipedic stance (ULS) for 30s. Five test evaluations were performed for each balance test. Postural control was found to be negatively correlated with increased adiposity, as the obese BMI group performed significantly poorer than the underweight, normal weight and overweight groups during BLS and ULS tests. The underweight, normal weight and overweight groups exhibited greater anterior-posterior stability in postural control during quiet stance. In addition, female displayed a trend of having a greater postural sway than male young adults, although it was evidenced in only some BMI groups. This study revealed that BMI do have an impact on postural control during both BLS and ULS. As such, BMI and gender-specific effects should be taken into consideration when selecting individuals for different types of sporting activities, especially those that require quiet standing.
  19. Ku PX, Abu Osman NA, Yusof A, Wan Abas WA
    PLoS One, 2012;7(7):e41539.
    PMID: 22848523 DOI: 10.1371/journal.pone.0041539
    Postural balance is vital for safely carrying out many daily activities, such as locomotion. The purpose of this study was to determine how changes in normal standing (NS) and standing with toe-extension (SWT) impact postural control during quiet standing. Furthermore, the research aimed to examine the extent to which the effect of these factors differed between genders.
  20. Abd Razak NA, Abu Osman NA, Wan Abas WA
    Disabil Rehabil Assist Technol, 2013 May;8(3):255-60.
    PMID: 22830946 DOI: 10.3109/17483107.2012.704654
    This study examined the kinematic differences between a body-powered prosthesis and a biomechatronics prosthesis as a transradial amputee performed activities that involve flexion/extension and supination/pronation of the wrist.
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