China 
Africa 
Explore chapters and articles related to this topic
Cardiovascular system
Published in A Stewart Whitley, Jan Dodgeon, Angela Meadows, Jane Cullingworth, Ken Holmes, Marcus Jackson, Graham Hoadley, Randeep Kumar Kulshrestha, Clark’s Procedures in Diagnostic Imaging: A System-Based Approach, 2020
A Stewart Whitley, Jan Dodgeon, Angela Meadows, Jane Cullingworth, Ken Holmes, Marcus Jackson, Graham Hoadley, Randeep Kumar Kulshrestha
Pain usually in the calf on exercise may be due to arterial narrowing or occlusion causing impaired blood flow to the areas distal to the blockage (peripheral ischaemia, peripheral arterial disease). The patient should be referred to a vascular surgeon with access to a vascular laboratory, where ankle brachial index (post-exercise if necessary) will give an early clue to the diagnosis, which can be confirmed by full Doppler ultrasound. If the patient is a candidate for a revascularisation procedure (surgery or interventional radiology) a full picture of the arterial tree will be needed for planning purposes, and this can be achieved by MR angiography, or CT angiography if MR is not possible.
Fundamentals of human gait and gait analysis
Published in Ivan Birch, Michael Nirenberg, Forensic Gait Analysis, 2020
Ambreen Chohan, Jim Richards, David Levine
Mid-stance is the phase of the gait cycle between opposite toe off and heel rise. However, in the past, the term has been used to describe the moment when the swing lower limb passes the stance lower limb, now usually referred to as feet adjacent. Ankle: During mid-stance and terminal stance, the tibia rotates forwards around the ankle, with the foot remaining flat on the floor, in a movement sometimes referred to as the mid-stance rocker. The ankle joint transitions from a plantarflexed to a dorsiflexed position, the movement being controlled by the eccentric contraction of the calf muscles, the triceps surae. The tibia externally rotates with coupled supination2 of the foot during mid-stance and terminal stance, the supination peaking in mid-stance before pronation of the foot occurs once again.Knee: The knee reaches its peak flexion of the stance phase at 15–20% of the gait cycle, then begins to extend again. The knee angle during mid-stance is highly dependent on the speed of walking.Hip: The hip continues to extend transitioning from a flexed to an extended position during mid-stance. This is generally achieved by a combination of inertia and gravity. As the opposite foot leaves the ground, the pelvis is supported by the stance phase hip, the swing phase side dipping slightly.Upper body: The trunk reaches its highest point during mid-stance. The lateral motion of the trunk also peaks during this phase as it moves towards the side of the stance lower limb. Like the feet, the arms also pass each other during mid-stance, following the motion of the opposite lower limb. The shoulders and pelvis both move through a neutral position, but in opposite directions, resulting in there being no twisting of the trunk.
Are We Built to Stand?
Published in Robert Bridger, A Guide to Active Working in the Modern Office, 2019
Plantar flexion of the ankle joint (pointing the toes downwards when sitting, or standing on tip-toe) activates the muscle pump (mainly through contraction of the soleus, or calf muscles) and pumps blood back up to the heart against gravity.
Changes in running biomechanics in master runners over age 50: a systematic review
Published in Sports Biomechanics, 2023
Matthew Klein, Chris Patterson
Masters runners demonstrate different injury rates and types compared to their younger counterparts (Lopes et al., 2012; McKean et al., 2006). There are higher rates of yearly injuries in masters runners, with a rate of 49% compared to 45% in younger runners (McKean et al., 2006). The injury types are also different, with younger runners suffering more knee-related issues, including patellofemoral pain syndrome and iliotibial band syndrome (Francis et al., 2019). Masters runners tend to experience a higher number of Achilles tendon, calf and hamstring injuries (McKean et al., 2006; Willy & Paquette, 2019). As rates of injury and the location of injury are different between masters and younger runners, it would stand to reason that differences in running biomechanics may also exist between these two groups of runners.
Validity, reliability, and normative data on calf muscle function in rugby union players from the Calf Raise application
Published in Sports Biomechanics, 2022
Kim Hébert-Losier, Te Manawa Ngawhika, Nicholas Gill, Carlos Balsalobre-Fernandez
This study was limited to male rugby union athletes and the results should not be generalised to female rugby union or sevens’ athletes given their unique requirements (Clarke et al., 2017; Sella et al., 2019). Although the data have the potential to inform the clinical management of injured players, our study involved uninjured players only to establish benchmark values and normative reference values. Therefore, individuals with a current Achilles tendon or calf muscle injury were excluded, and future research is needed to confirm the usefulness of the proposed calf muscle testing battery to establish the extent of injuries, track rehabilitation progress, and inform return-to-play decisions in rugby union. Finally, a set external load of 35 kg was used for the weighted power test based on prior research (Silbernagel et al., 2006), for ease of implementation, and to set a common benchmark load. Future work is required to determine whether implementing a relative load (e.g., percentage of body mass) would provide more meaningful outcomes than using an absolute load for rugby union players and ascertain generalisation across ages, levels, genders, and playing positions.
Kinematics of recreational male runners in “super”, minimalist and habitual shoes
Published in Journal of Sports Sciences, 2022
Kim Hébert-Losier, Steven J. Finlayson, Peter F. Lamb, Matthew W. Driller, Ivana Hanzlíková, Blaise Dubois, Jean-Francois Esculier, Christopher Martyn Beaven
Despite the majority of our participants remaining rearfoot strikers in FLAT (based on foot-ground angles being >8°; Altman & Davis, 2012), foot-ground angles were lower in FLAT versus OWN and VP4. This finding was anticipated given that running in more minimal compared to more conventional and/or cushioned shoes typically reduces foot-ground angles (Lussiana et al., 2013; Squadrone et al., 2015) and increases the relative plantar pressure in the forefoot region (Fuller et al., 2017; Lussiana et al., 2016). Ankle ROM in stance was also larger in FLAT, agreeing with findings from Hannigan and Pollard (2020) of greater ankle ROM in minimal versus traditional and maximal shoes. Minimal shoe running alters the loading profile at the foot and ankle and increases calf and Achilles tendon loads, suggesting that transitioning to minimal shoes should be gradual, progressive, and potentially incorporate calf and foot strengthening beforehand (Davis, 2014; Warne & Gruber, 2017) to reduce injury risk during transitioning.