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Abstract

To understand the normal series of biomechanical events of running, a comparative assessment to walking is helpful. Closed kinetic chain through the lower extremities, control of the lumbopelvic mechanism, and overall symmetry of movement has been described well enough that deviations from normal movement can now be associated with specific overuse injuries experienced by runners. This information in combination with a history of the runner's errors in their training program will lead to a more comprehensive treatment and prevention plan for related injuries.

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... Bu değişiklik, duruş fazının süresinin kısalmasına, sallanma fazının ise artmasına neden olur. Yürüyüşün aksine öne doğru hareket için gerekli olan güç, yerdeki bacaktan değil öne doğru salınan bacak ve koldan sağlanır (1,2). ...
... Lumbal bölge ve pelvis gibi diğer yapılar da bu durumdan etkilenir ve eklem hareket açıklıkları artar. Bu durum ise alt ekstremite yaralanma riskini artırır (2). ...
... Üst gövdenin dinamik komponentleri kostalar, sternum, torasik ve lumbar vertebraları içeren ligament ve kaslardan oluşur. Abdominal, paraspinal, gluteal ve pelvik taban kaslarını içeren gövde kasları koşu ile meydana gelen etki kuvvetlerinin absorbe edilmesi ve dağıtılmasında; bununla birlikte koşu sırasında gövde hareketlerinin etkin ve kontrollü bir şekilde devamlılığının sağlanmasında rol alır (2,6). Artan hızla beraber elit sporcularda rekreasyonel koşuculara göre daha stabil bir gövde çalışmalarda dikkat çekmektedir. ...
... Running popularity is increasing, with over 5000 organized marathons and 2 million finishers per year since 2015, according to the Association of Road Racing Statisticians (http://www.arrs.net). The repetitive activation of the lower extremity muscles during running and the cyclical nature of this sporting activity has been linked to high injury rates [1,2], especially when combined with high vertical loading rates. Foot-strike pattern is an important part of running biomechanics, given that the foot provides a solid base of support [3], absorbs and redistributes impact forces throughout the kinetic chain, and also contributes to propulsion and balance during locomotion [1,3]. ...
... The repetitive activation of the lower extremity muscles during running and the cyclical nature of this sporting activity has been linked to high injury rates [1,2], especially when combined with high vertical loading rates. Foot-strike pattern is an important part of running biomechanics, given that the foot provides a solid base of support [3], absorbs and redistributes impact forces throughout the kinetic chain, and also contributes to propulsion and balance during locomotion [1,3]. Foot-strike pattern in particular has been associated with an increased likelihood of certain types of running injuries [4]. ...
... The reliability of foot-strike angle and speed data were analyzed using a customizable statistical spreadsheet [22]. Two-way mixed effects single measurement intraclass correlation coefficient (ICC [3,1]), typical error (TE), and coefficient of variation (CV) with 90% confidence intervals [lower, upper] were calculated to quantify the relative (ICC) and absolute (TE and CV) reliability of measures. For the purpose of interpreting the ICC, the relative reliability of measures was considered to be poor (ICC < 0.40), fair (0.40 ≤ ICC < 0.75), good (0.75 ≤ ICC < 0.90), and excellent (ICC ≥ 0.90) [23]. ...
Article
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Two-dimensional running analyses are common in research and practice, and have been shown to be reliable when conducted on a treadmill. However, running is typically performed outdoors. Our aim was to determine the intra- and inter-rater reliability of two-dimensional analyses of overground running in an outdoor environment. Two raters independently evaluated 155 high-speed videos (240 Hz) of overground running from recreationally competitive runners on two occasions, seven days apart (test-retest study design). The reliability of foot-strike pattern (rear-foot, mid-foot, and fore-foot), foot-strike angle (°), and running speed (m/s) was assessed using weighted kappa (κ), percentage agreement, intraclass correlation coefficient (ICC), typical error (TE), and coefficient of variation (CV) statistics. Foot-strike pattern (agreement = 99.4%, κ = 0.96) and running speed (ICC = 0.98, TE = 0.09 m/s, CV = 2.1%) demonstrated excellent relative and absolute reliability. Foot-strike angle exhibited high relative reliability (ICC = 0.88), but suboptimal absolute reliability (TE = 2.5°, CV = 17.6%). Two-dimensional analyses of overground running outdoors were reliable for quantifying foot-strike pattern, foot-strike angle, and running speed, although foot-strike angle errors of 2.5° were typical. Foot-strike angle changes of less than 2.5° should be interpreted with caution in clinical settings, as they might simply reflect measurement errors.
... Hız arttıkça koşu daha dar bir genişlikte gerçekleşmektedir. Horizontal düzlemde kalça rotasyonu, ağırlık merkezinin yukarı ve aşağı düşmesini azaltır (Dugan & Bhat, 2005;Nicola & Jewison, 2012). Yürüme ve koşma arasındaki diğer farklar, koşunun tüm alt ekstremite eklemlerinde daha fazla hareket aralığı gerektirmesi (böylece yerçekimi merkezinin vertikal yükselmesi azaltılır) ve daha yüksek çarpma kuvvetleri nedeniyle yürümeden daha fazla miktarda eksantrik kas kasılması gerektirmesidir (Dugan & Bhat, 2005). ...
... Dizin fleksiyonu rektus femorisin eksantrik olarak kasılması ile yavaşlatılır, aynı kas öncesinde iliopsoas kasları ile birlikte kalça fleksiyonu yaratmaktadır ve bacak öne doğru taşınmaya başlanmıştır (Ounpuu, 1994). Uçuş fazı meydana gelirken rektus femoris ve tibialis anterior oldukça aktif kaslardır (Nicola & Jewison, 2012). Daha sonra hamstringler ve kalça ekstansörleri en aktif kaslar haline gelirler (Schache ve ark., 1999). ...
... Orta destek fazına kadar bu kaslar aktif haldedir. (Nicola & Jewison, 2012). Bacak öne taşınırken ilk salınım aşamasında kontralateral pelvisin yukarıda olmasından dolayı kalça abdüksiyondadır. ...
Article
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Bu derleme makalesi, koşu analizi ile ilgili bilgileri özetlemektedir. Makalede yürüme ve koşmanın karşılaştırılması ve ilişkisi açıklanmıştır. Koşunun destek ve salınım fazları ve bu fazların kendisine özgü özellikleri aktarılmıştır. Pelvis, kalça, diz, gövde, ayak eklemlerinin ve vücut kütle merkezinin ve farklı koşu hızlarındaki kinematiği elit sporculara özgü açılara bağlı kalınarak açıklanmaya çalışılmıştır. Eklem kinetikleri ve momentleri oluşturan kaslar belirtilmiştir. Koşu biyomekaniği ve koşu ekonomisi arasındaki ilişki değerlendirilmiştir. Edinilen biyomekanik bilgiye bağlı olarak koşu biyomekaniği ve koşu yaralanmaları arasındaki ilişki açıklanmaya çalışılmıştır. Aktarılan bilgilerin koşu anormallikleri, kompanzasyonlar, yaralanma mekanizmaları ve antrenman düzenlemeleri ile ilgili fikir vereceği düşünülmektedir.
... In addition, runners with a high weekly mileage were shortened in the posterior lower limb muscles by a greater amount than those running an average of 69 km per week or less (18) . Another study showed that in runners there was greater muscle shortening on the dominant side than on the non-dominant side (78) . A lack of flexibility in the gastrocnemius may lead to decreased range in both the knee and ankle joints (79) . ...
... Since the knee is never fully extended in running, Neely (41) reported that gastrocnemius shortening in isolation is unlikely to be the cause of lower limb injuries in running. Other studies found that a shortening in the calf muscles and the resulting ankle equinus has been found to predispose to muscle strains, plantar fasciitis, iliotibial band syndrome, Achilles tendinopathy and hamstring muscle strains (78,79) . In contrast, Craib et al (80) found that runners with decreased gastrocnemius flexibility had a better running economy. ...
... There has been some debate about whether muscle shortening is beneficial or detrimental to the performance of endurance runners, or whether it possibly even predisposes to injury (18,41,78,89) . ...
... Peak extension (around 10°) occurs at the take-off . Typical peak hip fl exion is around 30° (Nicola & Jewison, 2012). Th e knee is fl exed to 20-25° at the foot strike, reaches 45° fl exion in mid-stance and then extends to approximately 25° of fl exion at take-off (Novacheck, 1998). ...
... Abnormal kinematic parameters in the frontal plane (especially excessive ranges of motion) are most oft en linked to injury development. In the amortization phase, the pelvis drops to the side of the swing leg (generally not over 10°) and then returns to a neutral position throughout the propulsion phase (Nicola & Jewison, 2012). To compensate for this, the trunk is fl exed laterally, to the side of the stance leg. ...
... Internal hip rotation and consequential knee valgus are most oft en discussed in terms of injury development (Powers, 2003). Horizontal knee and ankle motion are minimal in normal running kinematics (Nicola & Jewison, 2012). ...
Article
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Runners are particularly prone to developing overuse injuries. The most common runningrelated injuries include medial tibial stress syndrome, Achilles tendinopathy, plantar fasciitis, patellar tendinopathy, iliotibial band syndrome, tibial stress fractures, and patellofemoral pain syndrome. Two of the most significant risk factors appear to be injury history and weekly distance. Several trials have successfully identified biomechanical risk factors for specific injuries, with increased ground reaction forces, excessive foot pronation, hip internal rotation and hip adduction during stance phase being mentioned most oft en. However, evidence on interventions for lowering injury risk is limited, especially regarding exercise-based interventions. Biofeedback training for lowering ground reaction forces is one of the few methods proven to be effective. It seems that the best way to approach running injury prevention is through individualized treatment. Each athlete should be assessed separately and scanned for risk factors, which should be then addressed with specific exercises. This review provides an overview of most common running-related injuries, with a particular focus on risk factors, and emphasizes the problems encountered in preventing running-related injuries.
... Lower regularity indicates less recurring behaviour, in other words, a more flexible or adaptive system (De La Cruz Torres et al., 2013;Meardon et al., 2011;Schütte et al., 2018). The ankle and the foot joints play a role during running to absorb and generate power (Deschamps et al., 2020;Nicola & Jewison, 2012). For example, Deschamps et al. (2020) showed that the ankle and the calcaneus-midfoot joint seemed to absorb power in a synchronised manner. ...
... Thus, the lowest observed regularity may reflect the demands produced by the forces related to the interaction with the ground. In this perspective, the foot joints may present even lower regularity than ankle since they are directly related to adapt the foot to surfaces (Dugan & Bhat, 2005;Nicola & Jewison, 2012). Future studies may consider use a multi-segmented foot (Leardini et al., 2019) to investigate this hypothesis. ...
Article
This study aimed to investigate the regularity of the lower limb joint kinematics in runners with and without a history of running-related injuries. The second aim was to verify if the movement pattern regularities are different among the lower limb joints. Eighteen asymptomatic recreational runners with and without a history of running-related injury participated in this study. Lower limb kinematics in the sagittal plane were recorded during running on a treadmill at a self-selected speed. The regularities of the time series of hip, knee, and ankle were analysed using sample entropy (SampEn). A mixed analysis of variance was used to investigate differences between groups and among joints. Runners with a history of injury had lower SampEn values than runners without a history of injury. Ankle kinematics SampEn was higher than that of the knee and hip. Knee kinematics had higher values of SampEn than that of the hip. Runners with a history of running-related injury had greater joint kinematic’s regularity. This result suggests that, even in asymptomatic runners, previous injuries could influence the movement pattern regularity. Also, the regularity was different among joints. The ankle demonstrated the lowest regularity, reinforcing the different functions that lower limb joints perform during running.
... 3 The stance phase is critical to performance as it is the only time where force can be applied to alter the body's forward propulsion, 1,4 and the swing phase is influenced by how an athlete can recover the segments during the flight phase in preparation for the next contact. 1 The cyclical pattern of running requires a coordinated interaction of muscles, [5][6][7][8][9] a given range of motion (ROM) to optimise motor recruitment patterns, 10 and strength to influence propulsion ability. 11 Sprint events (100-400 m) are distinguished from other competitive running events by the requirement for athletes to execute a blockstart. ...
... The D&B tool assessed areas of reporting, external validity, risk of bias, confounding bias, and power. Items 4,8,[13][14][15]17,19,21,23, and 24 were removed as they were not applicable to the studies of this review. Each item was scored as yes ('1'), no ('0'), or unable to determine ('0'), up to a maximum score of 18. ...
Article
Objective Para athletes with brain impairment are affected by hypertonia, ataxia and athetosis, which adversely affect starting, sprinting and submaximal running. The aim was to identify and synthesise evidence from studies that have compared the biomechanics of runners with brain impairments (RBI) and non-disabled runners (NDR). Design Systematic review. Method Five journal databases were systematically searched from inception to March 2020. Included studies compared the biomechanics of RBI (aged > 14 years) and NDR performing either block-starts, sprinting, or submaximal running. Results Eight studies were included, analysing a total of 100 RBI (78 M:22F; 18-38 years) diagnosed with either cerebral palsy (n = 44) or traumatic brain injury (n = 56). Studies analysed block-starts (n = 3), overground sprinting (n = 3) and submaximal running (n = 2), and submaximal treadmill running (n = 1). Horizontal velocity during starts, sprinting and self-selected submaximal speeds were lower in RBI. During sprinting and submaximal running, compared with NDR, RBI had shorter stride length, step length, and flight time, increased ground-contact time, increased cadence, and reduced ankle and hip range of motion. In submaximal running, RBI had decreased ankle-power generation at toe-off. Conclusions There is limited research and small sample sizes in this area. However, preliminary evidence suggests that RBI had lower sprint speeds and biomechanical characteristics typical of submaximal running speeds in NDR, including increased ground-contact times and reduced stride length, step length, and flight times. Meaningful interpretation of biomechanical findings in RBI is impeded by impairment variability (type, severity and distribution), and methods which permit valid, reliable impairment stratification in larger samples are required.
... There are different clinical or scientific questions that can be answered by the interdisciplinary field of biomechanics. Typically, biomechanical assessment of a healthy or injured athlete can be categorized into separate components such as motion and corresponding loads and forces [2]. These analyses can be used to detect potential injury mechanisms or to guide rehabilitation processes in the injured athlete [3]. ...
... Biomechanical analyses are frequently used in the evaluation of the individual running tech-nique [2]. Running is a cyclic movement and differs from walking due to the presence of a flight phase in which no foot touches the ground. ...
Chapter
The purpose of this chapter is to describe the interdisciplinary field of biomechanics and its importance in the evaluation of running. We will shortly describe the basic principles and origins of this scientific field and go into further details of new technical innovations. Then, a comprehensive overview of laboratory and field-based biomechanical analyses will be discussed in the light of implication for injury aetiology and prevention. Finally, we will end with a discussion on new research areas and implications for future research.
... Based on an initial inspection of the results, a further condition that the knee angle must be greater than 10° of flexion was added for determining the start point. The choice of 10° of flexion was because most runners tend to land with a knee flexion angle between 10 and 20° (Nicola et al. 2012). For all models the cost-function for the optimisation was the same. ...
Article
Mathematical models have the potential to provide insight into human running. Existing models can be categorised as either simple or complex, and there appears to be a lack of natural progression in model development. By sequentially adding complexity, there is the potential to determine how different mechanical components contribute to the biomechanics of running. In this study, a series of four models, of increasing complexity were developed in OpenSim: a simple spring-mass model, a two-segment model with a torsional spring at the knee and two three-segment models, one with a sprung knee and ankle and another with a sprung knee and actuated ankle. For each model, a forward simulation was developed and model predictions compared with experimental data from 10 forefoot runners. The results showed the spring-mass model overestimated the vertical displacement of the centre of mass (percentage difference: 43.6(22.4)-67.7(21.7)%) and underestimated the vertical ground reaction force (percentage difference: 13.7(8.9)-34.4(10.9)%) compared to the experimental data. Adding a spring at the knee increased the match with the vertical centre of mass displacement (percentage difference: 4.4(25.2)-18.4(40.2)%), however, geometry restrictions meant it was only possible to model approximately 60% of stance. The passive three-segment model showed a good match with centre of mass movements across most of stance (percentage difference in the vertical centre of mass displacement: 4.3(24.5)-21.3(19.2)%), however, actuation at the ankle was required to obtain a closer match with experimental kinetics and joint trajectories (e.g. vertical ground reaction force RMSD decreased by approximately 0.4BW). This is the first study to investigate models of increasing complexity of distance running. The results show that agreement between experimental data and model simulations improves as complexity increases and this provides useful insight into the mechanics of human running.
... Moreover, we observed significant fatigue-related increases in peak negative ankle joint power in the sagittal plane, irrespective of the used footwear. In this regards, we noted that at the time of initial ground contact, the ankle was within a few degrees from the neutral dorsi-/plantar flexion position [47]. After initial ground contact, ankle dorsiflexor muscles contract eccentrically thereby absorbing power (negative power). ...
Article
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Physical fatigue and pronated feet constitute two risk factors for running-related lower limb injuries. Accordingly, different running shoe companies designed anti-pronation shoes with medial support to limit over pronation in runners. However, there is little evidence on the effectiveness and clinical relevance of anti-pronation shoes. This study examined lower limb kinematics and kinetics in young female runners with pronated feet during running with anti-pronation versus regular (neutral) running shoes in unfatigued and fatigued condition. Twenty-six female runners aged 24.1±5.6 years with pronated feet volunteered to participate in this study. Kinetic (3D Kistler force plate) and kinematic analyses (Vicon motion analysis system) were conducted to record participants' ground reaction forces and joint kinematics when running with anti-pronation compared with neutral running shoes. Physical fatigue was induced through an individualized submaximal running protocol on a motorized treadmill using rate of perceived exertion and heart rate monitoring. The statistical analyses indicated significant main effects of "footwear" for peak ankle inversion, peak ankle eversion, and peak hip internal rotation angles (p
... Cushioning systems of technical running shoes are conventionally designed around these concepts (Tsouknidas et al., 2017), while considering the narrow base width support during the occurring impact (Nicola and Jewison, 2012). This results in a variety of footwear systems, as runners are classified by three different strike-patterns (Almeida et al., 2015), denoting the support area during impact: (a) heel-strike, where initial contact is made through the calcaneus, (b) midfoot strike, engaging the posterior and anterior portions of the foot simultaneously, and (c) forefoot-strike, during which runners primarily land on their metatarsals. ...
Article
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Etiologic factors associated to running injuries are reviewed, with an emphasis on the transient shock waves experienced during foot strike. In these terms, impact mechanics are analyzed from both, a biomechanical and medical standpoint and evaluated with respect injury etiology, precursors and morbidity. The complex interaction of runner specific characteristics on the employed footwear system are examined, providing insight into footwear selection that could act as a preventive measure against non-acute trauma incidence. In conclusion, and despite the vast literature on running-related injury-risks, only few records could be identified to consider the effect of shoe cushioning and anthropometric data on injury prevalence. Based on this literature, we would stress the importance of such considerations in future studies aspiring to provide insight into running related injury etiology and prevention.
... This anterior shift will change the mechanical advantage around the hip, knee, and ankle along with the differences in energy return from the shoe, we hypothesized changes in peak force, ground time, stride length, vertical impulse, knee range of motion during ground contact, hip range of motion, plantar flexion velocity, and center of mass vertical oscillation. Finally, since runners vary in anatomy and physiology, there may be differences in how someone would benefit from a different shoe in comparison with another runner (Ferber, Davis, & Williams, 2003;Nicola & Jewison, 2012;Williams, 2007). Given the previous research findings with the prototype VP shoe and the consumer availability of the VP shoe now, the primary purpose of this study was to determine if running in the consumer VP shoe would improve running economy compared to AB and ZS. ...
Article
The choice of marathon racing shoes can greatly affect performance. The purpose of this study is to metabolically and mechanically compare the consumer version of the Nike Vaporfly 4% shoe to two other popular marathon shoes, and determine differences in running economy. Nineteen subjects performed two 5-minute trials at 4.44m/s wearing the Adidas Adios Boost (AB), Nike Zoom Streak (ZS), and Nike Vaporfly 4% (VP) in random order. Oxygen uptake was recorded during minutes 3–5 and averaged across both shoe trials. On a second day, subjects wore reflective markers, and performed a 3-minute trial in each shoe. Motion and force data were collected over the final 30 seconds of each trial. VP oxygen uptake was 2.8% and 1.9% lower than the AB and ZS. Stride length, plantar flexion velocity, and center of mass vertical oscillation were significantly different in the VP. The percent benefit of the VP over AB shoe was predicted by subject ground time. These results indicate that use of the VP shoe results in improved running economy, partially due to differences in running mechanics. Subject variation in running economy improvement is only partially explained by variation in ground time.
... It is possible that there are different patterns of muscle utilization in the RF and VM during running (32). Sloniger et al (45). ...
Article
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Gutiérrez-Vargas, R, Martín-Rodríguez, S, Sánchez-Ureña, B, Rodríguez-Montero, A, Salas-Cabrera, J, Gutiérrez-Vargas, JC, Simunic, B, and Rojas-Valverde, D. Biochemical and muscle mechanical postmarathon changes in hot and humid conditions. J Strength Cond Res XX(X): 000-000, 2018-The aim of this study was to compare biochemical changes and mechanical changes in the lower-limb muscles before and after a marathon race in hot and humid conditions. Eighteen healthy runners participated in a marathon at between 28 and 34° C and 81% humidity in Costa Rica. Serum magnesium (Mg), creatine phosphokinase (CPK), lactate dehydrogenase, and hematocrit (HCT) were measured before and after the marathon. Tensiomyography measurements from the rectus femoris (RF) and vastus medialis, muscle displacement (Dm), contraction time (Tc), and velocities of contraction to 10 and 90% of Dm (V10 and V90) were obtained before and after the marathon. Postrace measurements showed a 544% increase in CPK (t(17): -6.925, p < 0.01), a 16% increase in HCT (t(17): -7.466, p < 0.01), a 29% decrease in Mg (t(17): 3.91, p = 0.001), a 2% decrease in body mass (t(17): 4.162, p = 0.001), a 4% increase in Tc of the RF (t(17): -2.588, p = 0.019), and a 12% increase in Dm of the RF (t(17): -2.131, p < 0.048) compared with prerace measurements. No significant biochemical or mechanical differences were found between runners in terms of their finish times. These findings showed that completing a marathon in hot and humid conditions induced a significant reduction in lower-limb muscle stiffness, body mass, and Mg, and increased neuromuscular fatigue, CPK, and HCT, because of muscle damage and dehydration. Knowledge of the effects of heat and humidity may be of value for coaches and sports medicine practitioners in developing effective hydration and recovery protocols for marathon runners in these special conditions.
... More speciically, the increase in plantar pressure peaks observed in this study in the pronated group may be associated with an ineicient functioning of the subtalar joint (responsible for the transformation of the tibial rotation into pronation), which is characteristic in individuals who exhibit excessive pronation movement during gait 7,18 . his ineiciency may be related to myoligamentar deicits, since the ankle ligaments counting on the help of the tibialis anterior, tibialis posterior, gastrocnemius and soleus muscles, are the main responsible for avoiding excessive pronation 17 . ...
Article
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Several studies have investigated the relationship between heel pronation with plantar pressure during gait. With a degree of variability and influence of the footwear, usually excessive pronation is associated with higher mechanical loads. However, larger loads are commonly associated with pronation. his study aims to compare the plantar pressure distribution among individuals with different pronation angles of the subtalar joint angle during gait with controlled speed. he maximum angle of the subtalar joint was determined by capturing images in the frontal plane and the pressure plant peaks were acquired by EMED pressure platform. he pronated group showed pressure plant peaks significantly higher in the lateral heel area (18%; p=0.031), medial heel (17%, p=0.034), lateral midfoot (30%; p=0.032) and medial midfoot (41%; p=0.018) when compared to the control group. Excessive pronation of the subtalar joint caused changes in plantar pressure distribution, and an increase in pressure plant peaks, especially in the heel and midfoot regions. This demonstrates the need for a specific care of this population, mainly because the increased pressure plant peaks is related to pain in the feet and onset of injuries.
... The greater varus changes in the current study may be associated with prolonged running time and distance in a marathon, which was different from prior running experiments with exertion. A previous study proposed knee varus rotation as a common biomechanical abnormality associated with running-related injuries [27]. For example, increased varus rotation at stance were found to increase the risk of iliotibial band syndrome [5]. ...
... This finding may be the result of the adaptability of the foot and ankle for different overground surfaces. When the supination of the foot creates propulsion at toe-off during running, the ankle is plantar flexed, the foot is inverted, and the forefoot is adducted [41]. Meanwhile, the foot was considerably plantar flexed on hard surfaces during running [42]. ...
Article
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Background: This study aimed to investigate the plantar loads of male non-rearfoot strike runners running on different overground surfaces at their preferred speeds. Methods: A total of 32 male runners with non-rearfoot strike were required to run for 15 m on concrete, synthetic rubber and grass surfaces at their preferred speeds. An insole sensor system was used to determine the runners' foot strike pattern and measure peak pressure, pressure-time integral, maximum force, force-time integral and contact area of the total foot and nine selected foot regions. Results: No significant differences on their preferred speeds were observed running on concrete, synthetic rubber and grass surfaces. No significant differences on plantar loads parameters of the total foot were found when running on the three overground surfaces. Running on concrete showed higher peak pressure in the lateral forefoot compared with grass and synthetic rubber (283.49 kPa vs. 264.31 kPa, P < 0.023; 283.49 kPa vs. 263.18 kPa, P < 0.019, respectively). Maximum force in the medial forefoot was lower when running on concrete compared with grass and synthetic rubber (40.16 %BW vs. 42.52 %BW, P < 0.042; 40.16 %BW vs. 43.21 %BW, P < 0.022, respectively). Conclusions: Repetitive and excessive plantar loads during long-distance running may result in loads-related injury in lower extremity skeletal tissues for non-rearfoot runners at preferred speeds. Therefore, male non-rearfoot strikers should choose the appropriate overground surface to reduce the risk of lower extremity musculoskeletal injuries.
... Unfortunately, similar to the before mentioned study, this study did not include measures of core muscle strength capacity either nor did they include a control group that did not receive a customized rehabilitation protocol. Assuming them to have a beneficial influence, many other interventional studies incorporated core stability exercises in their (secondary) prevention protocols as well [1,3,15,22,23,42,43,26,38]. However, it is impossible to compare or link our study results and possible clinical implications to this kind of retrospective interventional studies, as both research hypothesis and statistical approaches differ substantially. ...
Article
Background Although the vast majority of hamstring injuries in male soccer are sustained during high speed running, the association between sprinting kinematics and hamstring injury vulnerability has never been investigated prospectively in a cohort at risk. Purpose This study aimed to objectify the importance of lower limb and trunk kinematics during full sprint in hamstring injury susceptibility. Study Design Cohort study; level of evidence, 2. Methods At the end of the 2013 soccer season, three-dimensional kinematic data of the lower limb and trunk were collected during sprinting in a cohort consisting of 30 soccer players with a recent history of hamstring injury and 30 matched controls. Subsequently, a 1.5 season follow up was conducted for (re)injury registry. Ultimately, joint and segment motion patterns were submitted to retro- and prospective statistical curve analyses for injury risk prediction. Results Statistical analysis revealed that index injury occurrence was associated with higher levels of anterior pelvic tilting and thoracic side bending throughout the airborne (swing) phases of sprinting, whereas no kinematic differences during running were found when comparing players with a recent hamstring injury history with their matched controls. Conclusion Deficient core stability, enabling excessive pelvis and trunk motion during swing, probably increases the primary injury risk. Although sprinting encompasses a relative risk of hamstring muscle failure in every athlete, running coordination demonstrated to be essential in hamstring injury prevention.
... Rezende JM 1 *, Vitorino PVO 2 , Silva AA 2 , Pereira EN 2 , Lemos TV 3 , Sousa ALL 4 that demonstrably assesses the global muscle strength [7]. ...
Article
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Objectives: Assess the static baropodometric parameters and manual muscle strength before and during ve days of long-distance walking. Methods: Longitudinal study that assessed 25 male participants. Five assessments were made: baseline 20 days before the event (A0) and the remainder (A1, A2, A3 and A4) during the walk at the end of each day. For the assessment, a baropodometer and the hydraulic manual dynamometer. Results: The participants’ average age was 45.6±9.1 years and the mean body mass index 23.1±2.6kg/m2. The assessment included 250 feet: 204 neutral and 46 hollow. The maximum pressure in the right feet increased between A1 and A4 (p=0.025) and dropped between A2 and A3 (p=0.051). The contact surface of the right feet decreased between A0 and A1 (p<0.001); increased between A1 and A2 (p=0.001) and decreased between A2 and A3 (p<0.001). The contact surface of the left feet decreased between A0 and A1 (p=0.001); increased between A1 and A2 (p<0.001) and between A1 and A4 (p=0.002). The right anteroposterior core strength increased between A0 and A3 (p=0.001) and between A0 and A4 (p=0.009); on the left side, it increased between A0 and A2 (p=0.043), A0 and A3 (p=0.008) and A0 and A4 (p=0.001). The muscle strength did not change. Conclusion: Most participants in the sample possessed neutral feet. The burden on the lower right limb increased, which may have been due to limb dominance and/or changes in the route relief and the distance walked.
... In addition, our results did not indicate any correlation between the anterior pelvic tilt angle while standing statically and anterior pelvic tilt and hip abduction while performing a high speed run. Kinematic angles in this study are in agreement with angles reported from previous studies during a sprint (Higashihara, Nagano, Ono, & Fukubayashi, 2015;Nagano et al., 2014;Nicola & Jewison, 2012;Novacheck, 1998). This is the first study to incorporate time series analysis for statistical evaluation at the late swing phase with regards to pelvic changes in a standing position. ...
Article
Anterior pelvic tilt has been proposed to predispose the hamstring in soccer players to injury at the late swing phase during a sprint, however the mechanism on how the changes in the alignment would affect the kinematics are still unclear. Thirty-four male amateur soccer players were recruited for this study. Pelvic tilt was measured using the DIERS Formetric 4D. Lower extremity angles were recorded using an 8-camera Vicon motion capture system at 200 Hz while the athlete performed a high speed run on a motorised treadmill. Late swing phase was extracted from 5 running cycle which were later analysed using statistical parametric mapping (SPM). The results show that the increase of anterior pelvic tilt angle was significantly correlated with hip (r = −0.421 to −0.462, p = 0.015) and knee flexion (r = −0.424 to −0.472, p = 0.026) values. No other correlation was found between the anterior pelvic tilt and the angles at the coronal plane. By using time series analysis it was shown that the anterior pelvic tilt measured in a standing position would affect the adjacent segments’ kinematics while running as suggested in the kinetic chain theory; which would potentially predispose the soccer athletes to hamstring injury by maintaining knee extension.
... 31 The increase of GastL activity, established in our study, was related to kinematic changes of the foot observed with fatigue. Indeed, the gastrocnemius muscles have a role in frontal foot movement control 32 and work in synergy with the gluteal muscles to maintain vertical support. 33 It was not surprising to observe compensation of the GastL muscle during the unipedal dynamic balance test when the hip abductor was impaired. ...
Article
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Objective Determine whether hip abductor muscle fatigue influenced ankle kinematic and muscle activity during ankle-destabilized tasks. Design Cross-sectional study Methods Twenty-six healthy, active participants performed 2 tests (Star Excursion Balance Test, SEBT; Weight Bearing Inversion Test, WBIT) for assessment of dynamic balance and ability to control inversion. Participants were equipped with an ankle-destabilizing sandal in inversion and eversion to perform both tests, which were completed before and after a fatiguing exercise of hip abductor muscles (up to 50% reduction in strength). Electromyographic activity of peroneus longus (PL) and brevis (PB), tibialis anterior, gastrocnemius lateralis (GastL) and gluteus medius (GlutM) muscles were recorded. In addition, ankle kinematics were recorded using an inertial measurement unit. Results Hip abductor fatigue induced a significant decrease in SEBT scores in 3 directions (p<0.01). During SEBT, ankle supination decreased by 3.2° in the anterior and posteromedial directions (p<0.01). Muscle activity of GastL increased during achievement of 3 directions (p<0.05) in response to hip abductor fatigue. In posteromedial direction, PL (p<0.001) and GlutM (p<0.01) activity increased with fatigue. During WBIT, inversion angular velocity was not impacted by fatigue while, PB and GastL activity increased after fatiguing exercise (p<0.005). Conclusion A decrease in SEBT performance and EMG adaptations with proximal fatigue attest to the importance of the hip abductor muscle in dynamic postural control. This could have important implications in building injury prevention programs. Changes in ankle supination may reflect a protective strategy of the joint in response to hip fatigue.
... 5 Although running has a positive influence on one's physical health and fitness, it can also negatively impact the musculoskeletal system via running-related injuries. [6][7][8][9] Running is distinguished from walking (or other locomotive activities) by a number of characteristics. 10 Of note, we typically consider running to involve a flight phase where neither foot is in contact with the ground (see figure 1). ...
Article
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Grounded running predominantly differs from traditional aerial running by having alternating single and double stance with no flight phase. Approximately, 16% of runners in an open marathon and 33% of recreational runners in a 5 km running event adopted a grounded running technique. Grounded running typically occurs at a speed range of 2–3 m·s ⁻¹ , is characterised by a larger duty factor, reduced vertical leg stiffness, lower vertical oscillation of the centre of mass (COM) and greater impact attenuation than aerial running. Grounded running typically induces an acute increase in metabolic cost, likely due to the larger duty factor. The increased duty factor may translate to a more stable locomotion. The reduced vertical oscillation of COM, attenuated impact shock, and potential for improved postural stability may make grounded running a preferred form of physical exercise in people new to running or with low loading capacities (eg, novice overweight/obese, elderly runners, rehabilitating athletes). Grounded running as a less impactful, but metabolically more challenging form, could benefit these runners to optimise their cardio-metabolic health, while at the same time minimise running-related injury risk. This review discusses the mechanical demands and energetics of grounded running along with recommendations and suggestions to implement this technique in practice.
... Derrick et al. (6) provided the rationale that inversion increases coupled with IC knee flexion increases may lead to a more efficient way to accelerate the effective mass forward during running, which could potentially attenuate impact forces and reduce injury risk. The lack of MAX changes observed differs from previous reports (8,14), although our results were similar to the literature, with an average of approximately 8° (8,18). The experience of the runners could explain the lack of change studied here, and not being in an exhaustive state that may lead to altered mechanics (14). ...
Article
The initial contact and midstance angles may influence injury risk. Previous literature has not assessed these angles under the influence of new footwear for a non-exhaustive prolonged run or the relationship between the angles. To assess lower extremity kinematic changes and the relationship between kinematic parameters at initial contact and midstance with prolonged running under the influence of different types of footwear. Twelve experienced, recreational runners (6 male; 6 female; 24.8 ± 8.4 years; 70.5 ± 9.3 kg; 174.1 ± 9.7 cm) ran for 31 minutes at a self-selected pace for three testing sessions wearing maximalist, habitual, and minimalist shoes. Sixteen anatomical retroreflective markers and seven tracking clusters were placed on the participants' lower extremities. Kinematic data were collected every five minutes beginning at minute one. Initial contact angle (IC), maximum angle (MAX) during midstance, and latency (Tmax) between IC and MAX were calculated for the ankle and knee joints in the frontal and sagittal planes. No significant differences were observed between footwear. Rearfoot inversion (F3,33 = 9.72, p < .001) and knee flexion (F6,66 = 5.34, p < .001) at IC increased over time. No significant differences were detected for MAX over time. Tmax for dorsiflexion (F6,66 = 10.26, p < .001), rearfoot eversion, (F6,66 = 7.84, p < .001) and knee flexion (F6,66 = 11.76, p < .001) increased over time. Maximum eversion during midstance is related to the angle at initial contact, and regardless of footwear type, IC and Tmax increased over the duration of the run. No differences in the ankle and knee sagittal or frontal plane kinematics between minimalist, habitual, and maximalist footwear were observed During a self-paced run.
... If room or equipment is available, runners may be asked to run while the practitioner examines rearfoot eversion and pronation position at midstance. Typically, health care professionals use qualitative analysis (Nicola and Jewison, 2012), but recent advancements and access to video annotation software allow for quantification of rearfoot eversion angle using 2D video (Souza, 2016). ...
Article
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Many runners seek health professional advice regarding footwear recommendations to reduce injury risk. Unfortunately, many clinicians, as well as runners, have ideas about how to select running footwear that are not scientifically supported. This is likely because much of the research on running footwear has not been highly accessible outside of the technical footwear research circle. Therefore, the purpose of this narrative review is to update clinical readers on the state of the science for assessing runners and recommending running footwear that facilitate the goals of the runner. We begin with a review of basic footwear construction and the features thought to influence biomechanics relevant to the running medicine practitioner. Subsequently, we review the four main paradigms that have driven footwear design and recommendation with respect to injury risk reduction: Pronation Control, Impact Force Modification, Habitual Joint (Motion) Path, and Comfort Filter. We find that evidence in support of any paradigm is generally limited. In the absence of a clearly supported paradigm, we propose that in general clinicians should recommend footwear that is lightweight, comfortable, and has minimal pronation control technology. We further encourage clinicians to arm themselves with the basic understanding of the known effects of specific footwear features on biomechanics in order to better recommend footwear on a patient-by-patient basis.
... In the second half of the stance phase (of running) the COM is accelerated upward and forward. At the switch from walking to running, ground reaction forces increase, the stance phase shortens, and stance and swing phases are separated by a float phase, in which there is no contact with the ground ( Nicola & Jewison, 2012). No double stance phases exist during running. ...
Article
Arm swing during human gait has both passive and active components. The chapter presents a study conducted with normal subjects using electromyography (EMG) to describe patterns of arm and shoulder muscle activity in different gait conditions. These included normal forward walking, walking with immobilized arms, backward walking, power walking with accentuated arm swing, running, and load carriage. Complementary kinematic data are presented, too. Rhythmic muscle activity persists to some extent when both arms are immobilized during walking. Forward and backward walking involve dissimilar patterns of muscle activity, although the limb movements are very similar in both conditions. Likewise, power walking and running are characterized by different curves of EMG activity. Unimanual load carriage during walking affects muscle activities of both the loaded and the non-loaded arm. Research on normal arm swing provides a basis for clinical investigations of gait disorders.
... The gait cycle is the basic unit of measurement in gait analysis (Gage (1990) and it is defined as the series of events or movements of the lower limbs during locomotion in which one foot contacts the ground (initial contact -IC) to the moment in which the same foot touch the ground again (Dicharry, 2010;Novacheck, 1998). The gait cycle includes two main phases: i) the stance phase, which begins with the foot-ground contact and end when the foot loses contact with the ground; ii) and the swing phase, in which the foot is not touching the ground and it is demarcated by the foot strike and the toe off (Nicola & Jewison, 2012;Novacheck, 1998). ...
Thesis
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Running practice has become very popular in recent years. Successful distance running performance depends on multiple physiological factors, including a low energy cost to run at a given submaximal speed, which means a better running economy (RE). In addition, biomechanical factors can also influence RE and changes in running mechanics could lead to less energy usage at submaximal speeds, resulting advantageous to performance. Therefore, the purposes of this study was to investigate the relationship between RE and kinematic parameters in a group of recreational long-distance runners, and to analyse the changes in RE and kinematic parameters across different submaximal running speeds. Twenty subjects undergo three stages of submaximal running speeds on a treadmill. Simultaneously, respiratory gas exchange was measured using a metabolic cart, and kinematic parameters were gathered using high-resolution cameras for motion capture. We found a significant correlation (F = 0,510; p < 0,05) between RE and knee ROM during the stance phase. Knee ROM during stance phase was the single predictor of RE, explaining 26% of RE variance. Analysing RE and kinematic parameters across stages of submaximal running speeds, we found a speed-related trend for change. In conclusion, changes in running technique can influence RE, which might be important to induce improvements in long-distance running performance.
... Durante la marcha, esos periodos de doble vuelo no existen y dado que en ella la fase de apoyo de cada pie dura más del 50% del ciclo completo, en cada ciclo de la marcha hay dos periodos de doble apoyo en los que ambos pies están en contacto con el suelo (Novacheck, 1998;Cappellini et al., 2006;Kharb et al., 2011;Nicola y Jewison, 2012). Aunque se suele decir que en la marcha la fase de apoyo dura aproximadamente un 60% del ciclo y la fase de vuelo aproximadamente un 40% del ciclo (Umberger, 2010; Nicola y Jewison, 2012), la realidad es que a medida que la velocidad aumenta la fase de apoyo se hace más corta y la fase de vuelo más larga (Novacheck, 1998 Novacheck, 1998;Jiménez, 2004). ...
Article
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Un ciclo de carrera comienza en el momento en el que un pie toma contacto con el suelo y termina cuando vuelve a contactar con él. El objetivo del presente estudio es el de analizar en detalle los tiempos en los que se producen las diferentes fases del ciclo de la carrera y los momentos en los que la articulación subastragalina alcanza la máxima pronación y la posición neutra antes de la impulsión, así como las posibles relaciones entre los mismos. Veinte corredores recreacionales de edades comprendidas entre 20 y 28 años fueron grabados en un tapiz rodante a una velocidad comprendida entre 11 km/h y 12 km/h, con una cámara de vídeo a 60 fotogramas por segundo. Se midieron las siguientes variables temporales del ciclo de carrera: duración de la fase apoyo, duración de la fase de vuelo, duración del primer doble vuelo, duración del segundo doble vuelo, instante en que se produce la máxima pronación e instante en que se produce la posición neutra. Las duraciones medias de la fase de apoyo y de la de vuelo fueron, respectivamente, 38,90 ± 3,26% y de 61,10 ± 3,26% del ciclo completo. La duración similar de las dos fases de doble vuelo y la correlación significativa positiva entre ambos valores demuestra que el ciclo de carrera es bastante simétrico, independientemente de la pierna dominante. Los valores aquí encontrados para todas las variables temporales analizadas pueden servir de referencia para futuros estudios.
... During running, most of the forward force can be generated by the arm and leg swinging [27]. Therefore, the continuous nature of running gait from toe-off to toe-off, no certain point is assumed to be the beginning [18,28,29,30]. ...
Article
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This review article summarized the literature regarding running gait. It describes characteristics of running gait and running gait cycle, explains running anatomy in relation to lower and upper body mechanism; contribution of muscles, and joint running gait cycle. The concept of running kinematics and kinetics has described motion characteristics such as position, velocity, acceleration, and force applied during the running cycle. Running gait analysis techniques has discussed such as motion analysis, force plate analysis, and electromyography.
... Consequently, we selected basketball as the sport with the greatest development of the whole body since the sporting gesture of throwing requires lots of work from the shoulders, arms, and trunk, and the leg muscles and buttocks from jumping and running [18][19][20]. As a sport with greater development of the lower body, we chose running because, obviously, the lower body muscles are more active [21,22]. ...
Article
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Kinanthropometry allows us to analyze variations in physical dimensions and body composition. This study’s objective was to evaluate the kinanthropometric differences based on physical activity performance, depending on whether the lower body or the whole body is more or less potent and the differences with a sedentary population. We analyzed 131 individuals (74 men and 57 women), with an average age of 22.68 ± 2.98 years. We differentiated three populations: sedentary (n = 63), runners (n = 20), and basketball players (n = 48). Measurements and indices were obtained following the international protocol of the International Society for the Advancement of Kinanthropometry (ISAK). The results show differences between the populations regarding weight, height, wingspan, and certain perimeters, diameters, and morphotypes depending on the predominant training type and the sedentary population. These anthropometric measurements will allow the amateur athlete to compare between seasons or other moments of training, pay attention to their evolution, and assess the possibility of changes in training.
... On-ice propulsion involves frontal plane forces, which differs from sprinting on land. Sprinting on land involves force generation predominantly in the sagittal plane [12]. Propulsion occurs by pushing down and into the ground. ...
Article
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Appropriate performance tests are critical for documenting training, fatigue and injury-related changes. Functional performance testing can provide quantitative information on specialized sport movements. The single-leg, medial countermovement jump is an objective measure of frontal plane force, velocity and power, and is particularly applicable for ice hockey players given that ice skating involves applying lateral forces. This study assessed the short-term reliability (10 days) of the single-leg, medial countermovement jump performed by ten competitive male youth ice hockey players. Each participant performed three right and three left maximal single-leg, medial countermovement jumps from force plates. Measured variables included lateral and vertical takeoff velocity, lateral and vertical maximal force, maximal force above bodyweight, lateral and vertical peak concentric power, average concentric power, and average concentric power during the last 100 ms of push-off. Relative reliability was quantified by intraclass correlations. Absolute reliability and the smallest real difference were also calculated. The single-leg, medial countermovement jump had moderate-to-excellent test–retest reliability (ICC: 0.50–0.98) for all twelve variables of interest. These results suggest that the single-leg, medial countermovement jump is a reliable test for assessing frontal plane force, velocity and power in ice hockey players, and is a valid functional performance test for this population given the similarity to ice skating.
... In running, impact is absorbed through ankle joint eversion with dorsi-flexion from when the heel contacts the ground until mid-stance [1]. It has also been suggested that excessive eversion of the foot may induce limb injury during running [2][3][4]. ...
Article
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(1) Background: The purpose of this study was to investigate the effects of a rounded heel shoe (RHS) and rounded lateral heel shoe (RLHS) on impact and lower extremity stability as well as their relationships with comfort during running. (2) Methods: Twenty healthy male adults participated in the study. The data were collected using eight infrared cameras while participants were running at a speed of 2.7 m/s in three shoe conditions on an instrumented treadmill. (3) Results: The peak vertical ground reaction force (PVGRF) was statistically smaller for the RHS and RLHS compared with the normal shoes (NS) (p < 0.05). The range of motion of inversion–eversion at the ankle joint was statistically smaller for the RLHS compared with the NS and RHS (p < 0.05). Increased dorsiflexion of the ankle joint at heel contact was negatively related to the comfort of a running shoe, and increased dorsi-plantarflexion ROM was positively related to comfort. (4) Conclusions: Based on these results, a curved heel shape of a running shoe may provide a positive influence on the biomechanical function and the comfort of running shoes. Future study, including measurements of lower extremity muscle activations and long-term comfort, would be beneficial to help validate current findings and develop further applications.
... While running-related injury is multifactorial, the aforementioned running kinematics and kinetics are often targeted in clinical gait retraining interventions as a means to reduce pain and restore function in runners with knee and lower leg injuries [19][20][21][22][23]. These biomechanical measures are also frequently assessed in a clinical setting to determine injury risk [24][25][26]. Years of experience may also contribute to reduced injury via improved musculoskeletal tissue tolerance to repetitive loading or refined training programs that allow for appropriate rest time. However, determining the influence of experience on running form will inform clinicians as to whether faulty mechanics in novice runners is a predominant factor for higher injury risk when starting a running program and may offer an immediate option (gait retraining) to reduce risk. ...
Article
Purpose: Increased running experience and more time spent running appears to be advantageous in reducing injury risk, although the reason behind this is unclear. It is plausible that more experience results in better running mechanics leading to less injuries. Running mechanics are often screened during clinical assessments and targeted for correction in gait retraining, particularly those thought to be global indicators of injury or those associated with elevated knee joint loading. Examining the biomechanics of runners who are less-injury prone can improve our understanding of the significance of faulty running mechanics in relation to injury. Our goal was to examine if running experience was correlated to differences in kinematics and kinetics associated with increased knee joint loading and running-related injury risk. Methods: One hundred runners with varying experience ran on a pressure-sensing treadmill at a self-selected speed. Trunk and lower extremity kinematics, spatiotemporal measures, and ground reaction forces were collected. Multiple linear regression was used to assess the association between experience and three-dimensional hip kinematics, sagittal plane lower-extremity mechanics, and ground reaction forces while controlling for age and speed. Results: Increased running experience was not significantly associated with running mechanics. Increased age was significantly associated with reduced peak knee flexion and increased contact time. Running speed influenced several spatiotemporal, kinematic, and kinetic variables. Conclusion: Increased years of running experience does not appear to significantly influence running mechanics. However, age and running speed do influence biomechanical variables associated with injury in distance runners. Thus, there may be factors, other than running mechanics, that contribute to less risk in more experienced runners.
... Dieser bestimmt die Geschwindigkeit des Körperschwerpunkts während der anschließenden Flugphase und damit die Schrittlänge. Dabei kommt es zu einer Überschneidung der Schwungphasen beider Extremitäten und der charakteristischen doppelten Flugphase, die mit dem erneuten Kontakt endet (Hay, 1993;Nicola & Jewison, 2012;Novacheck, 1998;Strüder, 2013). Im Verlauf der beiden Schwungphasen wird der Fuß aus seiner Position hinter dem Körper nach vorne gebracht, wo der nächste Bodenkontakt stattfindet. ...
Thesis
In den leichtathletischen Sprintdisziplinen müssen Sportler in der Lage sein, innerhalb sehr kurzer Zeitintervalle (weniger als 100 ms bei Sprints) hohe Kräfte zu entwickeln. Biomechanische Merkmale wie Bodenkontaktzeiten, Flugzeiten oder Schrittfrequenzen stellen dementsprechend relevante Einflussgrößen der Leistung dar (u.a. Slawinski et al. 2010). Daher müssen diese gezielt angesteuert und trainiert werden. Andererseits können angestrebte Adaptionsmechanismen nicht ausgelöst werden, sodass in Folge keine Leistungssteigerung erfolgt. Der subjektiven Wahrnehmung sind Differenzen weniger Millisekunden jedoch nicht zugänglich oder nur indirekt ableitbar. Daher besteht die Forderung, die Ausprägung der relevanten Merkmale nicht nur gezielt zu trainieren, sondern auch trainings- und wettkampfbegleitend zu diagnostizieren. Messsysteme und -methoden nehmen somit sowohl in der Leistungsdiagnostik als auch in der Trainingssteuerung einen herausragenden Stellenwert ein (Fleming et al. 2010; Sands 2008; Wagner, 2006). Zur Erfassung biomechanischer Merkmale des leichtathletischen Sprints existieren eine Reihe von Messsystemen und -methoden wie beispielsweise dynamometrische Messsysteme (Kraftmessplatten), optometrische Systeme (OptojumpNext®) oder kamerabasierte Bewegungsanalysesysteme. Wesentlich beim Einsatz dieser Systeme sind zum einen die Auswahl und Erfassung der relevanten Merkmale mit der erforderlichen Genauigkeit und zum anderen die Qualität und Zeitstruktur der Ergebnisrückmeldung. Außerdem spielt der Grad der Beeinträchtigung beziehungsweise Beeinflussung des Athleten durch das Messsystem eine wichtige Rolle (Daugs, 2000). Diese und weitere Anforderungen (Einsetzbarkeit unter trainings- und wettkampfähnlichen Bedingungen sowie hohe Flexibilität) werden von den meisten Systemen jedoch nur zum Teil erfüllt. Technologische Entwicklungen der letzten Jahrzehnte haben dazu beigetragen, dass weitreichende Fortschritte der Messsysteme und -methoden erreicht wurden (Liebermann et al., 2002). Vor allem durch Verbesserungen der Mikroelektronik, Prozessortechnologie oder Methoden der kabellosen Datenübertragung können vorhandene Restriktionen minimiert werden. Dabei haben sich aufgrund ihrer kompakten Bauweise, des niedrigen Gewichts, des geringen Energiebedarfs und der hohen mechanischen Belastbarkeit Systeme auf Basis von Inertialsensoren als besonders geeignet erwiesen und halten verstärkt Einzug in den Leistungs- und Hochleistungssport verschiedener Sportarten (u.a. Chambers et al. 2015). Für den Einsatz von Messsystemen auf der Basis von Inertialsensoren zur Ableitung biomechanischer Merkmale im leichtathletischen Sprint liegen hingegen nur wenige Erkenntnisse vor (u.a. Bergamini et al., 2010; 2012). In diesem Gesamtzusammenhang leistet die vorliegende Forschungsarbeit einen Beitrag zur Weiterentwicklung biomechanischer Messsysteme und -methoden zum Einsatz in trainings- oder wettkampfähnlichen Anwendungsfeldern des leichtathletischen Sprints. Dazu werden Inertialsensoren in ein neuartiges Messsystem integriert. Neben dem technischen Aufbau bildet die Überprüfung der Messgenauigkeiten bei der Ableitung biomechanischer Merkmale einen Schwerpunkt der Arbeit. Zunächst wird der Forschungsstand bezüglich biomechanischer Einflussgrößen im leichtathletischen Sprint dargestellt, um zu zeigen welche Merkmale zur Ausprägung der disziplinspezifischen Leistungen beitragen und somit für eine Erhebung relevant sind (Kapitel 2). Im Anschluss wird aufgezeigt, dass im Rahmen einer trainingswissenschaftlichen Leistungsdiagnostik der Bedarf existiert, neue, tragbare Messsysteme in Training und Wettkampf zu integrieren (Kapitel 3). Mikroelektromechanische Sensoren und Systeme stellen diesbezüglich eine vielversprechende Alternative zu bisherigen Systemen und Methoden dar. Deren Aufbau, Funktionsweisen, Einsatzmöglichkeiten und bisherige Anwendungsgebiete zur biomechanischen Analyse sportlicher Bewegungen werden in Kapitel 4 dargestellt. Es wird dargestellt, welche Anforderungen bezüglich Hard- und Software ein Messsystem auf der Basis von Inertialsensoren (IMS) zur biomechanischen Analyse des leichtathletischen Sprints erfüllen muss, da diese Aspekte für die Systementwicklung maßgeblich sind. Die entsprechenden Defizite bisheriger Forschungsaktivitäten und die daraus abgeleiteten Forschungsziele der vorliegenden Arbeit werden in den Kapiteln 5 und 6 formuliert. Den Hauptteil der Arbeit bildet die Entwicklung (Kapitel 7 und 8), Validierung (Kapitel 9) und Anwendung (Kapitel 10) des Messsystems auf Basis von Inertialsensoren. Der technische Aufbau des Systems umfasst eine eingebettete Sensorik, Auswertealgorithmen und Funkmodule, wodurch eine Datenerfassung einer Gruppe von Sportlern zur Leistungsdiagnostik in labor- und feldbasierten (trainings- und wettkampfähnlichen) Anwendungen ermöglicht wird (Kapitel 7). Nach dem technischen Aufbaus des IMS werden für die jeweiligen Anwendungsszenarien (Sprünge und Sprints) Algorithmen zur automatisierten Eventdetektion entwickelt (Kapitel 8), mit deren Hilfe die Ableitung und Berechnung biomechanischer Merkmale erfolgt. Die Messgenauigkeit des Systems bei der Bestimmung der relevanten Einflussgrößen wird anschließend in zwei Validierungsstudien überprüft. Dazu werden die biomechanischen Merkmale durch das entwickelte System sowie geeignete Referenzsysteme (Kraftmessplatte, Kontaktmatte, Optojump) bei Dropjumps (Kapitel 9.1) und Sprints (Kapitel 9.2) erfasst und deren Übereinstimmung ermittelt. Dabei wird gezeigt, dass das IMS eine zuverlässige und auch für den Hochleistungssport hinreichend genaue Detektion biomechanischer Merkmale bei Sprüngen und Sprints ermöglicht und die Messgenauigkeiten vergleichbar mit vorherigen Studien oder besser sind (Bergamini et al., 2012; Patterson & Caulfield, 2010; Picerno et al., 2011; Purcell et al., 2006). Im Rahmen von zwei Anwendungsstudien zum Lang- und Hürdensprint wird das entwickelte System eingesetzt, um über den gesamten Verlauf der Wettkampfstrecke biomechanische Merkmale kontinuierlich zu erfassen (Kapitel 10). Es wird gezeigt, dass das neu entwickelte System die Gewinnung umfassender Daten und die Ableitung biomechanischer Merkmale ermöglicht, wie es durch den Einsatz existierender Systeme vor allem bei Trainings- und Wettkampfuntersuchungen bisher nicht möglich ist. Im Rahmen der Langsprintstudie wird gezeigt, dass sich in Folge von Ermüdung Änderungen hinsichtlich der kinematischen Schrittmerkmale ergeben, die sowohl für unterschiedliche Leistungsniveaus als auch unterschiedliche Stadien der Ermüdung (im Verlauf der Wettkampfstrecke oder nach Vorbelastung) divergieren. Auch im Hürdensprint werden mit Hilfe des Systems wichtige Erkenntnisse bezüglich der Merkmalsausprägung in Abhängigkeit des Leistungsniveaus erlangt. Es zeigt sich unter anderem, dass Sportler auf höherem Leistungsniveau nicht nur höhere Merkmalsausprägungen einer einzelnen Bewegung, sondern auch eine höhere Stabilität gegen Ende des Sprints aufweisen. Das entwickelte IMS ergänzt die bisher vorhandenen Systeme und leistet den angestrebten Beitrag zur Weiterentwicklung biomechanischer Messsysteme und -methoden zum Einsatz in trainings- oder wettkampfähnlichen Anwendungsfeldern des leichtathletischen Sprints. Die Anwendung des IMS im Rahmen einer trainings- und wettkampfbegleitenden Diagnostik oder zukünftiger Forschungsaktivitäten lässt die Ableitung wichtiger Erkenntnisse zur Leistungsstruktur im Leistungs- und Hochleistungsbereich der Sprintdisziplinen erwarten.
Chapter
The hamstring and quadriceps muscle complexes are commonly injured in athletes of all skill levels. Arriving at the correct diagnosis and rendering the appropriate treatment are predicated upon fundamental knowledge of the gross and functional anatomy of the hamstring and quadriceps complexes. The purpose of this chapter is to outline the anatomy of the anterior and posterior thigh musculature. The structure, function, and biomechanics of the three muscles of the hamstring and four muscles of the quadriceps will be discussed in detail. In addition to reviewing the normal anatomy, the most common pathologic conditions will be introduced so that the pathophysiology and treatment of these injuries can be discussed in greater detail in later chapters.
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The purpose of this pilot study was to investigate the effects of gender, speed, and tape on 2D lower extremity kinematics and stride characteristics during running. Eight healthy runners participated. Taping interventions (Leukotape, Kinesio Tape, no tape) and speeds (2.35 m/s, 3.35 m/s) were randomized and lower extremity stride kinematics were obtained using the Peak Motus System. Comparisons were made using descriptive statistics. Females exhibited greater hip and knee flexion, while males had greater ankle dorsiflexion and plantarflexion. Females spent more time in support while males spent more time in the air. Faster speed was associated with greater hip flexion and extension, peak knee flexion, and less time during contact. As a result, gender and speed seem to have effects on lower extremity stride kinematics, whereas type of tape does not.
Chapter
The purpose of classification in Paralympic sport is to promote participation in sport by people with disabilities by minimizing the impact of eligible types of impairment on the outcome of competition. This chapter provides detail on key elements of research design and measurement methods required for the development of evidence-based classification, thereby assisting researchers to improve the effectiveness of classification-focused research. It is divided into two sections. The first provides a brief overview of the structure of Paralympic sport, highlighting what sports must do to ensure that their classification systems are compliant with the requirements of the IPC. The second section provides a summary of how the principles articulated in the Position Stand can be operationally translated into programs of research, paying particular attention to important differences between physical, vision, and intellectual impairment. The chapter presents several steps, each of which represents an essential stage required for developing evidence-based systems of classification.
Article
Core muscles provide stability that allows generation of force and motion in the lower extremities, as well as distributing impact forces and allowing controlled and efficient body movements. Imbalances or deficiencies in the core muscles can result in increased fatigue, decreased endurance, and injury in runners. Core strengthening should incorporate the intrinsic needs of the core for flexibility, strength, balance, and endurance, and the function of the core in relation to its role in extremity function and dysfunction. Specific exercises are effective in strengthening the core muscles.
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La biomecánica es el área de estudio de componentes cinéticos y cinemáticos implicados en el movimiento corporal humano profundizando en elementos tales como fuerza muscular, rangos de movimiento, aceleración, velocidad y desplazamiento. En el deporte de alto rendimiento, el estudio de las variables biomecánicas que inciden en el gesto motor es de vital importancia para entender los mecanismos de control y adaptación del movimiento a actividades especificas, con el fin de desarrollar programas para mejorar la ejecución del movimiento en determinadas fases del gesto deportivo y prevenir lesiones a partir del estudio del gesto motor. Por tal motivo el objetivo de este artículo es realizar una revisión sistemática de la literatura sobre el uso de la tecnología para la evaluación e intervención de la biomecánica en el deporte de alto rendimiento
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Compression garments are widely used by athletes to improve athletic performance and to avoid potential injuries. Some compression garments are developed to exert pressure on muscle groups via thermoplastic polyurethane (TPU) membrane layers laminated on the textile surface. This study investigates the effect of novel TPU membrane patterns on muscle performance of the lower extremities and on the comfort parameters of air and water vapor permeability. Three novel running leggings with TPU membrane compression zones were designed to exert pressure on the major muscle groups used during running. Electromyography (EMG) measurements of the female participants wearing the designed leggings with TPU membranes, conventional leggings and shorts were recorded during a standardized squat protocol via a wireless surface EMG system. A repeated measures analysis of variance with a Greenhouse–Geisser correction determined that the mean root of mean square values for the EMG signals retrieved from the rectus femoris, vastus lateralis, gastrocnemius and hamstring muscles while wearing a specific legging design revealed statistically significant reductions in muscle activation. On the other hand, comfort tests exhibited low water vapor permeability and air permeability results when the textile surface was laminated with the TPU membrane. TPU membranes laminated on athletic wear to create compression zones could be effective in reducing muscle activation. Comfort performance is another essential design parameter that should be integrated into the design decisions. Large surfaces of solid TPU membranes should be minimized and surface textures should be employed for increased breathability.
Article
El objetivo del presente trabajo fue analizar la producción científica en el tenis en silla de ruedas (TSR), identificando, clasificando y categorizando los estudios indexados en la Web of Science y Medline (Pubmed). Se utilizaron los descriptores “wheelchair” y “tennis”. La muestra final de estudio fueron 73 artículos de los cuales se analizaron: 1) base de datos, 2) año, 3) tipo de publicación (artículo, revisión, conferencia, o artículo de opinión), 4) revista, 5) institución del primer firmante, 6) autor principal, 7) número de autores, 8) idioma, 9) deporte (TSR, o TSR en comparación de varias disciplinas de deporte adaptado, o comparación entre el TSR y el tenis convencional), 10) sexo de la muestra, 11) categoría, 12) nivel competitivo, y 13) disciplina principal del estudio. Los resultados mostraron un aumento de la producción científica del TSR en los últimos años, cuyas disciplinas de estudio son principalmente la fisiología, psicología del deporte y la biomecánica.
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Biomechanics is the area of study of kinematic and kinematic components involved in human body movement by delving into elements such as muscle strength, ranges of motion, acceleration, velocity and displacement. In high performance sport, the study of the biomechanical variables that affect the motor gesture is of vital importance to understand the mechanisms of control and adaptation of the movement to specific activities, in order to develop programs to improve the execution of the movement in certain phases of the sports gesture and prevent injuries from the study of the motor gesture. For this reason the aim of this article is to carry out a systematic review of the literature on the use of technology for the evaluation and intervention of biomechanics in high performance sport. key words: Rehabilitation, technology, sports medicine, athletic performance, biomechanics
Chapter
The knee joint is the largest joint in human body and allows a complex set of movements. The knee joint consists of medial and lateral tibiofemoral joints and the patellofemoral joint. Unlike hip joint articulation, the femoral and tibial surfaces of the knee are not a close fit to one another. The variation in geometry of the knee joint allows a wide range of motion during daily and sport activities. Due to strong association, the knee joint movements mostly linked to the hip and ankle joint movements. The knee joint sustains high forces and moments and also acts as a pivot between the two longest bones (femur and tibia) in human body, making it susceptible to injury.
Article
Córrer és una de les habilitats motrius més comuna dels infants i, per tant, s’ha de posar un especial interès a ensenyar-la correctament. Actualment, la combinació d’excés d’activitat física específica i sedentarisme està creant infants desequilibrats en l’àmbit motriu. Per això que l’objectiu d’aquest estudi va ser buscar i aplicar una metodologia que permetés a l’alumnat córrer còmodament a altes velocitats i evitar l’aparició d’actituds tòxiques perjudicials per a la seva motricitat.Per tal de veure’n els efectes es va fer un estudi comparatiu en un centre educatiu de Reus. Van participar-hi un total de 214 alumnes de cicle mitjà i superior durant un període de 6 setmanes, amb l’objectiu d’analitzar i comparar els resultats respecte a la velocitat i la coordinació de la cursa.
Article
Running is one of the most popular sport practices in the world. However, to our knowledge, none of the previous research about the characteristics of outdoor running makes a distinction between the different modalities of runners. Sixty-five healthy runners classified in sprinters, middle distance and long-distance runners performed five series of 100 metres on the synthetic outdoor track at competition pace. Muscle activity of lower limb muscles at initial contact and toe-off, involving the gluteus medius (GMED), gluteus maximus (GMAX), biceps femoris (BF), rectus femoris (RF), tiabilis anterior (TA) and medial gastrocnemius (MGAS), and spatiotemporal parameters were analysed. Sprinters showed high percentages of muscle activity at initial contact, in particular, the TA activity was the highest. The RF activity was significantly the lowest activity registered. At toe-off, sprinters showed the highest activity in all muscles analysed. Middle-distance runners had the highest activity of GMAX, BF and MGAS during the initial contact. In long-distance runners, the GMED and RF activity during the initial contact is highlighted, showing the highest activity of this phase. Different patterns of lower limb muscle activity and spatiotemporal parameters exist depending on the modality of the runner.
Chapter
The human hip consists of a stable but very mobile skeletal framework for the surrounding capsule, ligaments, muscles, nerves, and vasculature. Understanding the anatomy and the development of intra- and extra-articular pathologies is critical in any patient population, and careful consideration must go into the evaluation of a painful hip in the female athlete. The anatomy, biomechanics, and pathologies specific to the female athlete are explored in this chapter. Thorough knowledge of each of these leads to proper diagnosis and treatment of this cohort, with an expeditious return to sport being the goal.
Chapter
The hip is a constrained and encapsulated articulation between the concave acetabulum of the pelvis and the spherical femoral head. Despite this apparent simplicity, there exists a wide variation in the morphology and version of the proximal femur and acetabulum. This leads to a femoral head that is slightly out-of-round, an acetabulum that is horseshoe shaped, and a femoral head that moves relative to the socket such that it is not a true ball-in-socket joint. Additionally, there are more than 20 muscles and a variety of other soft tissues structures that span the joint contributing to the stability and function of the hip. Comprehensive knowledge of the proximal femur and pelvic anatomy, as well as the muscles, ligaments, labrum, and cartilage that surround the hip is essential to understanding the biomechanical properties involved in the equilibrium of forces needed for controlled hip joint motion.
Article
Objectives Hip/groin running-related injuries (RRI) are relatively uncommon. It is unclear if runners of either sex are disproportionately affected. Our objective was to systematically review differences in hip/groin RRIs between males and females. Data Sources A structured and comprehensive search of four medical literature databases was performed (PubMed, Embase, Ovid Medline, and CINAHL). Terms searched were: risk, epidemiology, hip injury, groin injury, overuse injury, running, sprinting, and track and field. Study Selection Studies reporting sex-specific data on hip/groin RRIs in adult runners were included. Data was extracted and reviewed independently by two authors. Study Appraisal and Data Synthesis Sex-specific injury rates, risk factors, and return to sport (RTS) following hip/groin RRI were extracted. Risk of bias was assessed using the Joanna-Briggs Institute Critical Appraisal Tool. Results 10 studies with 7,353 total runners were included: 2,315 (47%) males and 2,559 (53%) females. The mean age of included runners was 37.3 ± 8.9 years and mean weekly running distance was 10.4 ± 8.4 km. Hip/groin injuries comprised 10.1% (491/4,874) of total RRIs, including 6.3% of RRIs sustained by males and 11.0% by females. Three studies reported significantly higher rates of hip/groin RRIs in female runners. One study reported significantly higher rates of gluteus medius and adductor RRIs for females and males, respectively. One study identified female sex as an independent risk factor for hip/groin RRIs. Three studies reported on RTS after hip/groin RRIs: the pooled RTS rate was 81.4% (57/70) at 1 to 368 days after injury. Limitations Data was pooled when possible; however, there was considerable clinical, methodological, and statistical heterogeneity across studies. Conclusions Hip/groin RRIs comprise a greater percentage of total injuries among injured female runners relative to males. Females may be at a higher risk for sustaining hip/groin RRIs, though more research on risk factors and RTS is needed.
Article
PURPOSE The purpose of this study was to establish the criteria for measuring acute muscle fatigue using tensiomyography (TMG) by quantifying the trend of changes in TMG variables.METHODS Searches were conducted in the Web of Science and Pubmed databases using the keyword “Tensiomyography”. Sixteen studies which used TMG to measure acute muscle fatigue caused by acute exercises in rectus femoris or biceps femoris were included. All statistical data analyses were performed using Comprehensive Meta-Analysis software program.RESULTS The meta-analysis results indicated that the biceps femoris showed a significant (p<.05) decrease in all TMG variables of the elite athletes. Also, in the overall effects of maximum displacement and mean velocity until 90% Dm (Vc90) showed a significant (p<.05) decreasing trend. The rectus femoris showed a significant (p<.05) decreasing trend for maximum displacement (Dm) in the average person, while contraction time (Tc) showed a decreasing trend in elite athletes and overall.CONCLUSIONS These results suggest that TMG could be used as an indicator of muscle fatigue indicator, and will help to develop a more proper protocol to test the response of the body to muscle fatigue.
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Stress fractures are common in athletes and are more likely to occur in sports that involve repetitive and cyclical loads such as running and jumping. Stress fractures in the lower extremity have been linked to a multitude of intrinsic and extrinsic factors, including static and dynamic biomechanical considerations. Inspection of static biomechanical properties of the athlete should be performed in conjunction with a formal running assessment to assist in the identification of the contributing factors that may be linked to the occurrence of skeletal stress injuries. This chapter focuses on the methodology of carrying out a physical biomechanical examination and running assessment following a stress fracture. Descriptions of movements occurring in each of the three cardinal planes are discussed, along with other global factors of running technique. It will further identify certain patterns reported in the literature to be related to overuse stress injuries of bone and their link to stress fracture etiology.
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Locomotor patterns of running were studied using computerisation to synchronise electromyography (EMG) and cinematography (CMG). Surface electrodes monitored the muscle action potentials from 8 lower limb muscles from 10 male subjects, who ran on a treadmill at common jogging speeds of 2.5 m/s and 3.5 m/s. Averaged integrated electromyograms were formulated to represent action potential levels for various sub-sections of the running cycle. Correlation of the phasic activity of each EMG with the cyclic action of the lower limb was achieved by filming all running trials with a high speed camera. Beginning at foot contact the running cycle is dominated initially by muscle activity concerned with support. The co-contraction of vastus medialis, vastus lateralis, semimembranosus and tibialis anterior on a major level, and biceps femoris and triceps surae on a minor level, are associated with clockwise rotation of the thigh, leg and foot to provide a stable base during the early support phase. Lower limb stabilisation then gives way to the powerful driving thrust of the support phase. This period is characterised by increases in the electromyogram activity levels from triceps surae and biceps femoris muscles. The co-ordination of inertial effects and secondary muscular activity is associated with leg flexion as the thigh changes direction and leg extension during the swing phase of running. This conclusion is supported by both EMG and kinetic data. The increase in the running speed is associated with an increase in muscle action potential at sub-sections where the particular muscle is functional. This increase is parallelled kinetically by an increase in the resultant muscle moment of force.
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Dynamic gait evaluation allows examination of the intrinsic and extrinsic factors affecting an individual's ability to walk or run. This article identifies the gait cycle so that common terminology can be used to discuss and compare walking and running. The range of motion, or kinematics, used during gait can be seen subjectively in the hallway of the clinic but can be further objectified in a motion analysis laboratory. Kinetics, or the forces that cause the body to move, are collected in a laboratory environment. Understanding the internal and external forces acting on the body, the mobility they produce at the joints, and the corresponding effect on biomechanics helps identify sources of dysfunction. A discussion on economy highlights factors affecting the ability to move with a given amount of energy cost.
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Despite extensive research on running mechanics, there is still a knowledge gap with respect to the degree of relationship between mediolateral ground reaction forces (ML-GRF) and foot pronation. Our goal was to investigate whether differences exist in ML-GRF among runners that exhibit different degrees of pronation. Seventeen male and 13 female recreational runners ran with and without shoes while ML-GRF and frontal kinematics were collected simultaneously. Subjects were divided into groups based upon their peak eversion (low pronation, middle pronation, high pronation). Discrete parameters from the ML-GRF were peak forces, respective times of occurrence, and impulses. No significant differences were found between groups regarding the magnitude of ML-GRF. Based upon the relative times of occurrence, the peak medial GRF occurred closer to the peak eversion than the peak lateral GRF. Findings support the idea that the ML-GRF have less to do with pronation than previous research suggested.
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Cross-sectional experimental laboratory study. To examine differences in running mechanics between runners who had previously sustained iliotibial band syndrome (ITBS) and runners with no knee-related running injuries. ITBS is the second leading cause of knee pain in runners and the most common cause of lateral knee pain. Despite its prevalence, few biomechanical studies have been conducted to better understand its aetiology. Because the iliotibial band has both femoral and tibial attachments, it is possible that atypical hip and foot mechanics could result in the development of ITBS. The running mechanics of 35 females who had previously sustained ITBS were compared to 35 healthy age-matched and running distance-matched healthy females. Comparisons of hip, knee, and ankle 3-dimensional kinematics and internal moments during the stance phase of running gait were measured. The ITBS group exhibited significantly greater peak rearfoot invertor moment, peak knee internal rotation angle, and peak hip adduction angle compared to controls. No significant differences in peak rearfoot eversion angle, peak knee flexion angle, peak knee external rotator moment, or peak hip abductor moments were observed between groups. Females with a previous history of ITBS demonstrate a kinematic profile that is suggestive of increased stress on the iliotibial band. These results were generally similar to those reported for a prospective study conducted within the same laboratory environment.
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Humans have engaged in endurance running for millions of years, but the modern running shoe was not invented until the 1970s. For most of human evolutionary history, runners were either barefoot or wore minimal footwear such as sandals or moccasins with smaller heels and little cushioning relative to modern running shoes. We wondered how runners coped with the impact caused by the foot colliding with the ground before the invention of the modern shoe. Here we show that habitually barefoot endurance runners often land on the fore-foot (fore-foot strike) before bringing down the heel, but they sometimes land with a flat foot (mid-foot strike) or, less often, on the heel (rear-foot strike). In contrast, habitually shod runners mostly rear-foot strike, facilitated by the elevated and cushioned heel of the modern running shoe. Kinematic and kinetic analyses show that even on hard surfaces, barefoot runners who fore-foot strike generate smaller collision forces than shod rear-foot strikers. This difference results primarily from a more plantarflexed foot at landing and more ankle compliance during impact, decreasing the effective mass of the body that collides with the ground. Fore-foot- and mid-foot-strike gaits were probably more common when humans ran barefoot or in minimal shoes, and may protect the feet and lower limbs from some of the impact-related injuries now experienced by a high percentage of runners.
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We investigated the control and function of arm swing in human walking and running to test the hypothesis that the arms act as passive mass dampers powered by movement of the lower body, rather than being actively driven by the shoulder muscles. We measured locomotor cost, deltoid muscle activity and kinematics in 10 healthy adult subjects while walking and running on a treadmill in three experimental conditions: control; no arms (arms folded across the chest); and arm weights (weights worn at the elbow). Decreasing and increasing the moment of inertia of the upper body in no arms and arm weights conditions, respectively, had corresponding effects on head yaw and on the phase differences between shoulder and pelvis rotation, consistent with the view of arms as mass dampers. Angular acceleration of the shoulders and arm increased with torsion of the trunk and shoulder, respectively, but angular acceleration of the shoulders was not inversely related to angular acceleration of the pelvis or arm. Restricting arm swing in no arms trials had no effect on locomotor cost. Anterior and posterior portions of the deltoid contracted simultaneously rather than firing alternately to drive the arm. These results support a passive arm swing hypothesis for upper body movement during human walking and running, in which the trunk and shoulders act primarily as elastic linkages between the pelvis, shoulder girdle and arms, the arms act as passive mass dampers which reduce torso and head rotation, and upper body movement is primarily powered by lower body movement.
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We investigated the relationship between functional and static foot posture and medial tibial stress syndrome in distance runners. Twenty-eight runners with a clinical diagnosis of medial tibial stress syndrome and 12 asymptomatic runners were assessed with the Foot Posture Index to measure static overpronation. Range of motion was measured at the talocrural joint, with the knee extended and flexed as was range of motion at the first metatarsophalangeal joint and the angular difference between the neutral and relaxed calcaneal stance positions. Each participant was then videotaped while running on a treadmill shod and unshod. This videotape was analyzed using freeze frame to identify abnormal or mistimed pronation at each phase of gait. The results were analyzed using logistic regression to give the probability that a runner is likely to experience medial tibial stress syndrome, predicted from the static measurements and dynamic observations. Variables identified as being significant predictors of medial tibial stress syndrome were the difference between the neutral and relaxed calcaneal stance positions, range of motion of the talocrural joint with the knee extended, early heel lift and abductory twist during gait, and apropulsive gait. Runners with suspected symptoms of medial tibial stress syndrome should be assessed dynamically and statically for abnormal or mistimed pronation.
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The biomechanics of the foot and ankle is important to the normal function of the lower extremity. The foot is the terminal joint in the lower kinetic chain that opposes external resistance. Proper arthrokinematic movement within the foot and ankle influences the ability of the lower limb to attenuate the forces of weightbearing. It is important for the lower extremity to distribute and dissipate compressive, tensile, shearing, and rotatory forces during the stance phase of gait. Inadequate distribution of these forces could lead to abnormal stress and eventual breakdown of connective tissue and muscle. Pathologies such as heel spurs, hallux valgus, neuromas, hallux limitus, shin splints, and nonspecific knee pain result from abnormal mechanics of the foot and ankle. The use of orthotics to re-establish the normal biomechanics of the foot and ankle have profound clinical applications. The combined effect of muscle, bone, ligaments, and normal biomechanics will result in the most efficient force attenuation in the lower limb. J Ortho Sports Phys Ther 1987;9(1):11-16.
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Cross-sectional experimental laboratory study. To investigate the relationships between hip strength and hip kinematics, and between arch structure and knee kinematics during prolonged treadmill running in runners with and without patellofemoral pain syndrome (PFPS). Hip weakness can lead to excessive femoral motions that adversely affect patellofemoral joint mechanics. Similarly, foot mechanics, which are influenced by foot structure, are also known to influence patellofemoral joint mechanics. Thus, proximal and distal factors should be considered when studying individuals with PFPS. Twenty recreational runners with PFPS (5 male, 15 female) and 20 matched uninjured runners participated in the study. Hip abduction and hip external rotation isometric strength measurements were collected before and after a prolonged run, while the arch height index was recorded on all runners before the run. Lower extremity kinematic data were collected at the beginning and end of the run. Two-way repeated-measures analyses of variance (ANOVAs) were used for analysis. Both groups displayed decreases in hip abductor and external rotator strengths at the end of the run. The PFPS group displayed significantly lower hip abduction strength [(kg x cm)/body mass] compared to controls (PFPS group: begin 15.3, end 13.5; uninjured group: begin 17.3, end 15.4). At the end of the run, the level of association between hip abduction strength and the peak hip adduction angle for the PFPS group was statistically significant, indicating a strong relationship (r = -0.74). No other associations with hip strength were observed in either group. Arch height did not differ between groups and no significant association was observed between arch height and peak knee adduction angle during running. Runners with PFPS displayed weaker hip abductor muscles that were associated with an increase in hip adduction during running. This relationship became more pronounced at the end of the run. Therapy, level 5.
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An increased knowledge of the biomechanics of normal walking and running will improve our understanding of the possible mechanisms of pathology and ultimately improve the treatment of pathology and injury. Running, a natural extension of walking, involves increased velocities, joint range of motion, forces, muscle activity, joint moments, and joint powers as compared with walking. These differences not only stress the mechanics of the body to a greater extent but also contribute to the development of injury due to overuse. With the use of modern computerized gait analysis techniques that provide objective information, comprehension of normal and also pathologic walking and running patterns can be improved.
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The amount of mechanical energy transferred by two-joint muscles between leg joints during squat vertical jumps, during landings after jumping down from a height of 0.5 m, and during jogging were evaluated experimentally. The experiments were conducted on five healthy subjects (body height, 1.68-1.86 m; and mass, 64-82 kg). The coordinates of the markers on the body and the ground reactions were recorded by optical methods and a force platform, respectively. By solving the inverse problem of dynamics for the two-dimensional, four-link model of a leg with eight muscles, the power developed by the joint (net muscular) moments and the power developed by each muscle were determined. The energy transferred by two-joint muscles from and to each joint was determined as a result of the time integration of the difference between the power developed at the joint by the joint moment, and the total power of the muscles serving a given joint. It was shown that during a squat vertical jump and in the push-off phase during running, the two-joint muscles (rectus femoris and gastrocnemius) transfer mechanical energy from the proximal joints of the leg to the distal ones. At landing and in the shock-absorbing phase during running, the two-joint muscles transfer energy from the distal to proximal joints. The maximum amount of energy transferred from the proximal joints to distal ones was equal to 178.6 +/- 45.7 J (97.1 +/- 27.2% of the work done by the joint moment at the hip joint) at the squat vertical jump. The maximum amount of energy transferred from the distal to proximal joints was equal to 18.6 +/- 4.2 J (38.5 +/- 36.4% of work done by the joint moment at the ankle joint) at landing. The conclusion was made that the one-joint muscles of the proximal links compensate for the deficiency in work production of the distal one-joint muscles by the distribution of mechanical energy between joints through the two-joint muscles. During the push-off phase, the muscles of the proximal links help to extend the distal joints by transferring to them a part of the generated mechanical energy. During the shock-absorbing phase, the muscles of the proximal links help the distal muscles to dissipate the mechanical energy of the body.
Article
Because of the nature of running, the forces encountered require a proper coordination of joint action of the lower extremity to dissipate the ground reaction forces and accelerations through the kinetic chain. Running-related muscle fatigue may reduce the shock absorbing capacity of the lower extremity and alter running kinematics. The purpose of this study was to determine if a bout of exhaustive running at a physiologically determined high intensity, changes running kinematics, impact accelerations, and alters shock attenuating capabilities. It was hypothesized that as a result of fatigue induced by an exhaustive run, running kinematics, impact accelerations at the head and shank, acceleration reduction, and shock attenuation would change. A within-subject, repeated-measures design was used for this study. Twelve healthy, competitive male and female distance runners participated. Subjects performed 2 testing sessions consisting of a VO2max treadmill protocol to determine the heart rate at ventilatory threshold and a fatigue-inducing running bout at the identified ventilatory threshold heart rate. Kinematic data included knee flexion, pronation, time to maximum knee flexion, and time to maximum pronation. Acceleration data included shank acceleration, head acceleration, and shock attenuation. No significant differences resulted for the kinematic or acceleration variables. Although the results of this study do not support the original hypotheses, the influence of running fatigue on kinematics and accelerations remains inconclusive. Future research is necessary to examine fatigue-induced changes in running kinematics and accelerations and to determine the threshold at which point the changes may occur.
Article
In walking, humans prefer a moderate step width that minimizes energetic cost and vary step width from step-to-step to maintain lateral balance. Arm swing also reduces energetic cost and improves lateral balance. In running, humans prefer a narrow step width that may present a challenge for maintaining lateral balance. However, arm swing in running may improve lateral balance and help reduce energetic cost. To understand the roles of step width and arm swing, we hypothesized that net metabolic power would be greater at step widths greater or less than preferred and when running without arm swing. We further hypothesized that step width variability (indicator of lateral balance) would be greater at step widths greater or less than preferred and when running without arm swing. Ten subjects ran (3m/s) at four target step widths (0%, 15%, 20%, and 25% leg length (LL)) with arm swing, at their preferred step width with arm swing, and at their preferred step width without arm swing. We measured metabolic power, step width, and step width variability. When subjects ran at target step widths less (0% LL) or greater (15%, 20%, and 25% LL) than preferred, both net metabolic power demand (by 3%, 9%, 12%, and 15%) and step width variability (by 7%, 33%, 46%, and 69%) increased. When running without arm swing, both net metabolic power demand (by 8%) and step width variability (by 9%) increased compared to running with arm swing. It appears that humans prefer to run with a narrow step width and swing their arms so as to minimize energetic cost and improve lateral balance.
Article
The role of arm swing in running has been minimally described, and the contributions of arm motion to lower extremity joint kinematics and external force generation are unknown. These contributions may have implications in the design of musculoskeletal models for computer simulations of running, since previous models have usually not included articulating arm segments. 3D stance phase lower extremity joint angles and ground reaction forces (GRFs) were determined for seven subjects running normally, and running under two conditions of arm restraint. When arm swing was suppressed, the peak vertical GRF decreased by 10-13% bodyweight, and the peak lateral GRF increased by 4-6% bodyweight. Changes in peak joint angles on the order of 1-5 deg were observed for hip flexion, hip adduction, knee flexion, knee adduction, and ankle abduction. The effect sizes (ES) were small to moderate (ES<0.8) for most of the peak GRF differences, but large (ES>0.8) for most of the peak joint angle differences. These changes suggest that suppression of arm swing induces subtle but statistically significant changes in the kinetic and kinematic patterns of running. However, the salient features of the GRFs and the joint angles were present in all conditions, and arm swing did not introduce any major changes in the timing of these data, as indicated by cross correlations. The decision to include arm swing in a computer model will likely need to be made on a case-by-case basis, depending on the design of the study and the accuracy needed to answer the research question.
Article
Cross-sectional controlled laboratory study. To investigate the kinematics of the hip, knee, and rearfoot in the frontal and transverse planes in female distance runners with a history of tibial stress fracture. Tibial stress fractures are a common overuse injury in runners, accounting for up to half of all stress fractures. Abnormal kinematics of the lower extremity may contribute to abnormal musculoskeletal load distributions, leading to an increased risk of stress fractures. Thirty female runners with a history of tibial stress fracture were compared to 30 age-matched and weekly-running-distance-matched control subjects with no previous lower extremity bony injuries. Kinematic and kinetic data were collected using a motion capture system and a force platform, respectively, as subjects ran in the laboratory. Selected variables of interest were compared between the groups using a multivariate analysis of variance (MANOVA). Peak hip adduction and peak rearfoot eversion angles were greater in the stress fracture group compared to the control group. Peak knee adduction and knee internal rotation angles and all joint angles at impact peak were similar between the groups. Runners with a previous tibial stress fracture exhibited greater peak hip adduction and rearfoot eversion angles during the stance phase of running compared to healthy controls. A consequence of these mechanics may be altered load distribution within the lower extremity, predisposing individuals to stress fracture.
Article
Playing sports barefoot has been contested since the very beginnings of athletic competition. Even today, some data suggest that shoes may limit the adaptive pronation that occurs after footstrike during running gait. This pronation likely protects runners from injury. Boardsport participants who perform their sports barefoot on the water seem to be at risk for foot and ankle injuries. The high-impact forces in gymnastics place participants at risk for foot and ankle injuries, as well. Swimming and diving have a low rate of foot and ankle injuries. The risk of ankle sprain in beach volleyball, which is played barefoot, seems to be lower than that for indoor volleyball, played wearing shoes. Martial arts place competitors at risk for injuries to the foot and ankle from torsional and impact mechanisms. Athletes who hope to return to barefoot competition after injury should perform their rehabilitation in their bare feet.
Article
The biomechanics of the foot and ankle are important to the normal function of the lower extremity. The foot is the terminal joint in the lower kinetic chain that opposes external resistance. Proper arthrokinematic movement within the foot and ankle influences the ability of the lower limb to attenuate the forces of weightbearing. It is important for the lower extremity to distribute and dissipate compressive, tensile, shearing, and rotatory forces during the stance phase of gait. Inadequate distribution of these forces could lead to abnormal stress and the eventual breakdown of connective tissue and muscle. The combined effect of muscle, bone, ligaments, and normal foot biomechanics will result in the most efficient force attenuation in the lower limb. This article will look specifically at the normal biomechanics of the foot and ankle. J Orthop Sports Phys They 1985;7(3):91-95.
Article
Athletes often suffer from recurrent or chronic overuse symptoms of the lower extremities. During the office visit it is essential to analyse the patient's shoes, gait cycle, lower extremities and, especially, the talocrural, subtalar and more distal joints of the ankle and foot. The basic (clinical) biomechanical analysis can be supplemented by radiographs, treadmill and video analysis and mirror table (podoscope) examinations. Ideally, successful pain relief by correction of the observed abnormality with an orthotic device completes the diagnostic procedure, especially if symptoms return soon after the removal of the device. In treatment custom-made, expensive orthotics should not be prescribed for overuse symptoms without an obvious malalignment, for asymptomatic athletes with a malalignment, or for symptoms in which the causal relationship between the biomechanical abnormality and symptoms is difficult to see. Strict indications for prescription of orthotics and close cooperation between the attending physician, physical therapist and orthotist are prerequisites for obtaining good, long-lasting results.
Article
Electrogoniometers were used to measure step length, frequency and movements of hip, knee and ankle with increases in running velocity. Experienced distance runners ran on a horizontal treadmill at speeds ranging from 183 to 396 m/min. Runners increased velocity by increasing both step length and frequency; length playing a greater part at lower velocity and frequency playing a greater part as velocity approached 396 m/min. As velocity increased, hip extension showed little change while hip flexion increased markedly causing the amplitude to increase. During the swing phase, knee extension decreased while flexion increased with an increased amplitude. During the support phase, knee extension decreased while flexion increased with no change in the amplitude. Ankle flexion, extension and amplitude did not change with increase in velocity. (C)1970The American College of Sports Medicine
Article
Hindfoot function involves eccentric loading of the subtalar joint and repetitive strain of the calcaneal soft tissues. Both are induced by the serial pattern of foot support. The subtalar joint experiences rapid eversion following heel strike and subsequent inversion during terminal stance. Although these actions reduce the rotatory strain on the ankle joint, they also challenge the local soft tissues and controlling muscles. Compression and traction of the soft tissues about the heel are normal events during each walking cycle. Loading the limb at the onset of stance causes heel pad compression. Conversely, the plantar fascia and tendo Achillis are subjected to significant traction as body weight is transferred onto the forefoot during the latter half of the single limb support period. The intensity of hindfoot stress increases with the vigor of activity. Running creates symptoms that do not arise with ordinary walking. Microtrauma is cumulative. Also, the aging process reduces the ability of tissue to accommodate repetitive force.
Article
A biomechanical study of 13 runners which consisted of 2 male sprinters, 5 experienced joggers, and 6 elite long-distance runners were studied. We obtained hip, knee, and ankle joints motions in the sagittal plane and electromyographic data from specific muscle groups. As the speed of gait increased, the length of stance phase progressively decreased from 62% for walking to 31% for running and to 22% for sprinting. The sagittal plane motion increased as the speed of gait increased. Generally speaking, the body lowers its center of gravity with the increased speed by increasing flexion of the hips and knees and magnifying dorsiflexion at the ankle joint. Electromyographic activity about the knee demonstrated increased activity in the quadricep muscle group and hamstring group with increased speed. Mus cle function about the ankle joint demonstrated that the pos terior calf musculature which normally functions during the midstance phase in walking became a late swing phase muscle and was active through the first 80% of stance phase, as compared to 15% in walking. Beside the changes in the electromyographic activity of the muscles, the anterior compartment muscles of the calf undergo a concentric contracture at the time of initial floor contact during running and sprinting but undergo an eccentric contrac tion during walking.
Article
The purposes of this study in the recreational runner were to describe and compare lower extremity sagittal range of motion and vertical body displacement for slow and fast paces during treadmill and overground running, and to compare timing of the running phases at the two paces. Vertical displacement of the body, and flexion and extension of the hip, knee, and ankle were measured with a motion analysis system at 200 hertz as the subjects self-selected the two paces. No statistically significant differences were seen when comparing sagittal motion on a treadmill with overground running. Statistically more vertical displacement during overground running was recorded when compared with treadmill running. Peak vertical force was near midstance when the ankle, knee, and hip approached maximum flexion. Results demonstrated that during a slow pace the approximate arcs of motion were: ankle, 50 degrees; knee, 95 degrees; and hip, 40 degrees. During running at a fast pace, the hip required more extension in early swing; the hip and knee required more flexion in middle and late swings. The fact that ankle motion did not change with the different speeds gave credence to the belief that push-off, or toe-off, is not the source of power in running.
Article
The purpose of this study was to describe and compare the muscle firing patterns of the muscles controlling the ankle during running. Fine-wire electrodes monitored the activity of the gastrocnemius, soleus, peroneus brevis, tibialis posterior, and tibialis anterior muscles during 3 paces of running. High-speed film was used to synchronize the electromyographic data with the phases of running. The subjects were 15 recreational and competitive runners who were injury-free. There were 3 significant findings. First, the firing patterns of all of the posterior muscles demonstrated peak activity during midstance phase. Thus, these muscles were contracting in an eccentric fashion to control ankle dorsiflexion as the center of gravity passed over the ankle. Second, the tibialis anterior muscle fired above the fatigue threshold for 85% of the time. This may account for the high number of fatigue-related injuries to the tibialis anterior muscle seen in runners. Third, there was a significant increase of activity in the peroneus brevis muscle as the pace increased. This indicates the importance of training this muscle when pace is increased. Using this information, a sport-specific effective and efficient exercise program for runners can be developed.
Article
This review article summarizes the current literature regarding the analysis of running gait. It is compared to walking and sprinting. The current state of knowledge is presented as it fits in the context of the history of analysis of movement. The characteristics of the gait cycle and its relationship to potential and kinetic energy interactions are reviewed. The timing of electromyographic activity is provided. Kinematic and kinetic data (including center of pressure measurements, raw force plate data, joint moments, and joint powers) and the impact of changes in velocity on these findings is presented. The status of shoewear literature, alterations in movement strategies, the role of biarticular muscles, and the springlike function of tendons are addressed. This type of information can provide insight into injury mechanisms and training strategies. Copyright 1998 Elsevier Science B.V.
Article
Athletes who participate in high-impact sports involving running, jumping, or contact are at risk for forefoot injury. These injuries occur as a result of acute trauma or chronic overuse. Some athletes may be predisposed to injury because of preexisting foot deformity, such as cavus, hallux valgus, or Achilles contracture. This article reviews the common causes of forefoot pain in the athlete. The most common causes of forefoot pain in the athlete are metatarsal stress fracture, interdigital neuroma, sesamoid pathology, metatarsalgia, hallux rigidus, hallux valgus, and turf toe. The pathophysiology, clinical presentation, and treatment of these conditions are discussed.
Article
The purpose of this review article is to summarise the literature to date regarding the movement of the lumbar spine, pelvis and hips during running gait. Both two-dimensional and three-dimensional studies are analysed to illustrate the apparent coordination in the angular kinematics of each of these segments during running. Knowledge of this coordination is essential in order to facilitate the successful rehabilitation of running injuries to the back, pelvis, hip and thigh.
Article
In conclusion, core stability exercise is an evolving process, and refinement of the clinical rehabilitation strategies is ongoing. Two major foci are addressed in contemporary core stability programs: motor control and muscle capacity. Both of these factors have considerable foundation in the literature and can be seen as a progression of exercise rather than conflicting approaches. Importantly, the clinical efficacy of these approaches is being realized in clinical trials. Further work is required, however, to refine and validate the approach, particularly with reference to contemporary understanding of the neurobiology of chronic pain.
Article
It has been suggested that during running proper coordination between subtalar pronation/supination and knee flexion/extension via tibial rotation is important to attenuate ground reaction impact forces (GRIF). Lack of coordination over time may produce a wide range of injuries. It was hypothesized that increasing stride length would result in higher GRIF. It was also hypothesized that alterations in stride length would result in changes of the subtalar/knee coordination. Six subjects ran under 3 different stride lengths (normal stride, understride and overstride) at their self-selected pace. Sagittal, rear view kinematic data and GRIF kinetic data were collected. The subtalar/knee coordination was evaluated via timing and relative velocity measures. Repeated measures ANOVA were performed on these measures with a Tukey post-hoc analysis conducted where appropriate (p<0.01). Increased stride length produced significant increases in GRIF and significantly augmented the differences between rearfoot and knee angular velocities. A change in the rearfoot angle curve from a unimodal (1 minimum) to a bimodal (2 minimums) parabolic configuration was also observed. The appearance of the additional minimum was attributed to the increased impact with the ground. The results indicated that increases in GRIF via changes in stride length could disrupt the coordination between subtalar and knee joint actions.
Article
In most cases, a detailed history provides the information that is necessary for the clinician to diagnose the injured runner correctly; however, to treat the injury and guide a successful rehabilitation program, the physical examination must go beyond the standard regional musculoskeletal examination. The victims (tissue injury) and the culprits (biomechanical deficits) must be identified to facilitate treatment (Table 3). Gait and other dynamic assessments help to reveal underlying deficits in function that may have contributed to injury. In short, the entire functional kinetic chain must be considered and weak links identified.
Article
Physical activity, including running, is important to general health by way of prevention of chronic illnesses and their precursors. To keep runners healthy, it is paramount that one has sound knowledge of the biomechanics of running and assessment of running gait. More so, improving performance in competitive runners is based in sound training and rehabilitation practices that are rooted firmly in biomechanical principles. This article summarized the biomechanics of running and the means with which one can evaluate running gait. The gait assessment techniques for collecting and analyzing kinetic and kinematic data can provide insights into injury prevention and treatment and performance enhancement.
Article
Neuromusculoskeletal models are used to investigate hamstring mechanics during sprinting. We show that peak hamstring stretch occurs during late swing phase and is invariant with speed, but does depend on tendon compliance and the action of other muscles in the lumbopelvic region. The insights gained are relevant for improving the scientific basis of hamstring strain injury prevention and rehabilitation programs.
Article
The purpose of this study was to characterize the effect of speed and influence of individual muscles on hamstring stretch, loading, and work during the swing phase of sprinting. We measured three-dimensional kinematics and electromyography (EMG) activities of 19 athletes sprinting on a treadmill at speeds ranging from 80% to 100% of maximum speed. We then generated muscle-actuated forward dynamic simulations of swing and double float phases of the sprinting gait cycle. Simulated lower extremity joint angles and model predicted excitations were similar to measured quantities. Swing phase simulations were used to characterize the effects of speed on the peak stretch, maximum force, and negative work of the biceps femoris long head (BF), the most often injured hamstring muscle. Perturbations of the double float simulations were used to assess the influence of individual muscles on BF stretch. Peak hamstring musculotendon stretch occurred at approximately 90% of the gait cycle (late swing) and was independent of speed. Peak hamstring force and negative musculotendon work increased significantly with speed (p<0.05). Muscles in the lumbo-pelvic region had greater influence on hamstring stretch than muscles acting about the knee and ankle. In particular, the hip flexors were found to induce substantial hamstring stretch in the opposite limb, with that influence increasing with running speed. We conclude that hamstring strain injury during sprinting may be related to the performance of large amounts of negative work over repeated strides and/or resulting from a perturbation in pelvic muscle coordination that induces excessive hamstring stretch in a single stride.
Article
Both kinematics and kinetics of the lower limb have been shown separately to be related with a history of tibial stress fractures (TSFs) in female runners. However, it is likely that these factors interact together to increase the risk of a TSF. This study was conducted to determine which combination of kinematic and kinetic factors are the best predictors of retrospective TSF in female distance runners. Total 30 female runners who had previously sustained a TSF were recruited, along with an age and mileage matched control group (n=30). Subjects ran overground at 3.7m/s while kinematic and kinetic data were recorded. Five trials from each subject were used for data analysis and ensemble means were calculated for both groups. The kinematic variables of peak hip adduction (HADD), peak knee internal rotation (KIR) and knee adduction (KADD), peak rearfoot eversion (RFEV) were entered into a binary logistic regression along with the kinetic variables of vertical instantaneous load rate (VILR) and absolute free moment (FM). The variables HADD, FM and RFEV were able to correctly predict a history of TSF in 83% of cases. Increases in HADD, FM and RFEV (odds ratios of 1.29, 1.37 and 1.18) were associated with an elevated risk of having a history of TSF. The addition of VILR, KIR and KADD did not improve the ability to predict previous injury. Based on these results, HADD, FM and RFEV appear to be the most important of the variables of interest in terms of predicting retrospective TSF in female runners.
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American Academy of Orthopaedic Surgeons Symposium on the Foot and Leg in Running Sports
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Running and sprinting: a dynamic analysis St Paul (MN): Gillette Children's Hospital
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Biomechanics of distance running. Champaign (IL): Human Kinetics Books
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St Paul (MN): Gillette Children's Hospital
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