Two-dimensional analyses of sprint kinetics are commonly undertaken but often ignore the metatarsal-phalangeal (MTP) joint and model the foot as a single segment. The aim of this study was to quantify the role of the MTP joint in the early acceleration phase of a sprint and to investigate the effect of ignoring the MTP joint on the calculated joint kinetics at the other stance leg joints. High-speed video and force platform data were collected from four to five trials for each of three international athletes. Resultant joint moments, powers, and net work at the stance leg joints during the first stance phase after block clearance were calculated using three different foot models. Considerable MTP joint range of motion (>30°) and a peak net MTP plantar flexor moment of magnitude similar to the knee joint were observed, thus highlighting the need to include this joint for a more complete picture of the lower limb energetics during early acceleration. Inclusion of the MTP joint had minimal effect on the calculated joint moments, but some of the calculated joint power and work values were significantly (P < .05) and meaningfully affected, particularly at the ankle. The choice of foot model is therefore an important consideration when investigating specific aspects of sprinting technique.
Neil E. Bezodis, Aki I.T. Salo and Grant Trewartha
Troy R. Garrett and Peter J. Neibert
Injury to the plantar fascia, whether acute or chronic, is common among many populations. A conventional multiple-treatment approach is commonly administered by health care providers, consisting of controlling inflammation, managing pain, and promoting healing. Frequently, the initial treatment for plantar fasciitis is targeted at increasing dorsiflexion range of motion by stretching the gastroc-soleus musculature. It has been theorized that inflexibility of the gastroc-soleus complex can lead to excessive pronation and overcompensation of the plantar fascia at the first metatarsal phalangeal joint, therefore increasing the stress at the medial calcaneal insertion. Therefore, it is deemed that gastrocnemius–soleus stretches are a beneficial treatment in the initial stage of a plantar fasciitis treatment or rehabilitation program.
Focused Clinical Question:
Is a gastrocnemius–soleus stretching program, as a stand-alone treatment variable, effective in the treatment of plantar fasciitis?
Scott Van Horne and Darren J. Stefanyshyn
Acceptance of the klap speed skate was fully realized on the world speed skating scene in 1997. However, one of the most important unknowns regarding the klapskate was the positioning of the point of foot rotation (pivot point), which is believed to play an important role in optimizing klapskate performance. The purposes of this study were to explore the ankle, knee, and hip joint mechanical changes that occurred when the pivot point location was modified, and to determine whether maximal ankle torques provide predictive ability as to where the optimal pivot point positioning is for a skater. We tested 16 proficient skaters at three pivot point (PP) locations, ranging from just in front of the metatarsal-phalangeal joint to just in front of the first phalangeal joint. Of the 16 skaters, 10 were tested at a fourth position: tip of the toe. Push phase kinetics and kinematics were measured on a modified slide board. The optimal PP for each skater was defined as the position that allowed him to generate the most total push energy. Maximum voluntary static torque measures of the ankle and knee were collected on a Biodex dynamometer. Overall, anterior pivot point shifting led to a significant increase in ankle energy generated and a decrease in knee energy generated, with no significant change at the hip joint. We found no significant correlations between the static strength measures and the skaters' optimal pivot points.
Oladipo O. Eddo, Bryndan W. Lindsey, Shane V. Caswell, Matt Prebble and Nelson Cortes
second metatarsal phalangeal joint markers and the anterior–posterior laboratory axis. 18 Toe-in foot progression angle was quantified as positive. Participants were instructed to “direct the toes from your dominant limb inward towards your non-modified limb immediately after your heel contact. On
Felipe García-Pinillos, Carlos Lago-Fuentes, Pedro A. Latorre-Román, Antonio Pantoja-Vallejo and Rodrigo Ramirez-Campillo
length was defined as the length of the foot from the heel cup (most posterior portion of the calcaneus) to the center of the medial joint space of the first metatarsal phalangeal joint. 16 Arch stiffness, a measure of the amount of deformation per unit of load, was defined as the change in arch height