Obesity Essay

balance of the body also flexion on the back leg when the ball is being released ending in a plantar flexion position .

*John Guido and Sherry Werner make a point that “The stride leg functions to dynamically stabilize the hip and knee joints in a single leg stance to maintain standing posture for

Six standing trials include 1) single dominant leg stance on a firm surface (SDFS), 2) single non-dominant leg stance on a firm surface (SNDFS), 3) double leg stance on a firm surface (DFS), 4) single dominant leg stance on a wobble board (SDWB), 5) single non-dominant leg stance on a wobble board (SNDWB), and 6) double leg stance on a wobble board (DWB). The order of the standing trials will be randomized. A two minute testing period will be recorded for each standing condition. During testing, participants will be instructed to position barefoot with the hands akimbo for as still as possible for both a firm surface and a wobble board conditions. During all one leg stance trials, participants will be instructed to flex the knee of the contralateral

The angular velocity begins at the support foot plant phase and continues into the follow-through phase. For a player to achieve a maximal velocity instep kick, this is one of the main biomechanical principles to focus on improving, as the greater the velocity of the kicking leg, the greater the power. The kicking leg is modelled as a three link kinetic chain composed by the segmental forces of the thigh, shank and foot, where angular velocities are measured (Nunome, Asai, Ikegami & Sakurai, 2002). The kicking leg’s forward motion is initiated by the rotation of the pelvis, and the thigh of the kicking leg being brought forwards with

The purpose of the barefoot running study article is to determine whether runners can achieve the propose of favorable kinematic changes and reduction in loading rate after a progressive training program. The article designed a study that hypothesized that not all individuals would experience a decrease in initial loading rate facilitated by increased ankle plantar flexion after a progressive barefoot running program but would further a relationship that exist between changes in initial loading and sagittal ankle

In Ober test physical therapist will be holding the knee of the testing leg in flexion and in

When absorbing ground reaction forces during physical activity, rather than using the muscular prime movers of the lower extremity, females act on the use of bony configuration and articular cartilage and ligaments to absorb these forces (4). Newton’s third law states that for every action, there is an equal and opposite reaction. In any action of sports whether a soccer player makes a cut on the field, or a basketball player lands from grabbing a rebound, the reaction force is actually greater than an

When designing exoskeletons it is necessary to understand the biomechanics of human walking. The human walking gait cycle is represented on a scale of 0% to 100% and includes several notable phases shown in Figure 1. The structure of a human leg contains total of 7 Degrees of Freedom (DOF) with three rotational DOFs located at the hip, one at the knee and three at the ankle. Degrees of Freedom are directional factors that affect the range of independent motion in a system. Biomechanical measures of level ground walking at the hip, knee, and ankle are shown in Figure 2. The power requirement curves display the general power fluctuation for the hip as positive or near zero, the knee as negative, and the ankle is as equally balanced. This outcome signifies

There were several different interventions performed aimed at increasing range of motion, balance/proprioception, and to increase strength of the right lower extremity. Following the initial examination and evaluation a brief therapeutic exercise period ensued. The gastrocnemius and soleus were both stretched against a wall each for two sets of 60 seconds to help increase dorsiflexion range of motion (Radford, Burns, Buchbinder, Landford, Cook, 2006). Active range of motion for dorsiflexion, plantarflexion, inversion and eversion was performed on a wobble board while seated for 20 repetitions in each directions to increase range of motion, but more importantly to improve proprioception (Bernier and Perrin, 1998). Plantar flexion strength was addressed by utilizing green thera-tubing around the forefoot with the patient holding the other end of the tube. This was performed for one set of 20 repetitions. Body weight squats using a railing for support were chosen as they are a closed kinetic chain exercise that challenges the gluteus muscle group as well as hamstrings while also causing dorsiflexion of the ankles (Gryzlo SM, Patek RM, Pink M, Perry J, 1994). Closed chain exercises were started initiated at the first visit as they cause an increase in joint compressive forces which can lead to increased stability, increased muscle activation, and decreased joint shearing forces (Harter, 1996). Supine bridges on a 55 cm theraball were performed for 20 repetitions to address the

The article “Muscular contributions to hip and knee extension during the single limb stance phase of normal gait: a Theoretical Framework for Crouch Gait” by Allison Arnold, Frank Anderson, Marcus Pandy, and Scott Delp investigates the biomechanics of normal gait in hopes to uncover ideas to help determine treatments for crouch gait. Crouch gait is a bothersome abnormality that affects the gait pattern of people who suffer from the condition of cerebral palsy. It’s characterized by excessive flexion of the hips and knees during standing and excessive use of metabolic energy to complete a single gait cycle. Currently, the treatments for this condition are limited and have unpredictable outcomes due to the unknown biomechanical causes of the excessive flexion in crouch gait. These treatments include surgical lengthening of hamstrings, ankle-foot orthoses, and intense stretching regimens, with patients experiencing results ranging from no improvement in their symptoms to dramatic improvements. The vast array of results from treatments are due to the little understanding medical professionals have of not only abnormal gait patterns (such as crouch gait) but of normal gait as well (Arnold, Anderson, Pandy, and Delp, 2005). Despite the article’s title relating to crouch gait, the purpose of the study conducted was to examine and quantify the accelerations of normal hip and knee movements that were induced by specific muscles during the single limb stance phase and to rank these

During walking and running, leg muscles produce forces that impact the tibiofemoral joint. These forces can have a negative impact on the development, health and maintenance of the cartilage and meniscus in that joint (and increased load on the knees and the tibiofemoral joint can result in osteoarthritis). The tibiofemoral load is varied depending on the muscle coordination patterns. The laboratory created a musculoskeletal model of subject to analyze the tibiofemoral load, and an optimization framework to calculate the load from muscle coordination. Using the model and optimization framework, the laboratory was able to understand the impact of different muscle coordination on the tibiofemoral load. The laboratory was able to precisely predict tibiofemoral forces when compared to in vivo measurements during the early stance phase, but overshot its prediction during the late stance phase. The over-prediction of the tibiofemoral load was due to the extended activity of the gastrocnemius and the rectus femoris. The laboratory was able to modify the activity of these two muscles to increase resemblance with in vivo measurements. The laboratory was also able to identify distinct changes in muscle activity that could decrease tibiofemoral load. A decrease in activation of the rectus femoris and gastrocnemius and an increase in activation of the soleus, gluteus medium and uniarticular hip flexors can decrease the tibiofemoral forces during late

One study began looking into the presence of knee valgus during the DJT compared to other movements. The participants included 22 female handball and soccer players who were instructed to perform five sidestep cuts and three vertical drop jumps. The purpose of this was to find the difference in the knee valgus angles between six thigh marker clusters, and then to find the impact of those on the cross-talk effect between them. The drop jump test was performed using a 30 centimeter box and participants performed a maximal jump after landing. Measurements of knee valgus were taken during the contact phase and initial contact and were compared using the six different thigh markers. During the drop jump test, there was about a 15 degree of peak valgus between the marker sets. There seemed to be varied cross-talk between the two tests. This was the first study to quantify the differences in knee valgus between these two tests.13 Therefore, more research is needed to find correlations between the presence of knee valgus and other possible ACL injury

Figure 1. A photo of stages 1 and 2 of the instep kick, the approach and foot planting, of a beginner athlete.

Hip and knee joints extend, and the gluteus-maximus contract in order for hamstrings and quadriceps to lengthen. As the leg touches the ground, the body is propelled forwards due to muscles engaging in concentric isotonic contractions.

Jumping is a movement which is fundamental to a vast majority of sports (Grimshaw et.al 2006). The goal of a jump may be to try and achieve the longest or highest jump possible, as in long jump and high jump; or they may be performed to intercept the opposition for example a header in football or defensive block in basketball (Matavulj et.al, 2001) (Juarez et.al, 2011). An example of a jump is a counter-movement jump as defined by (Marshall & Moran 2013) as being a form of vertical jump which involves a preparatory movement downwards before a forceful extension of the hip, knee and ankle moves the body upwards into the concentric phase. A jump which can be related to both vertical jump at toe-off (concentric) and counter-movement jump at the landing phase (eccentric) is a drop jump.