Plantar Pressures and Foot Posture: New Study
A new study published in Gait and Posture has found associations between foot posture and plantar pressures in healthy individuals.
This paper compared “normal”, pes planus and pes cavus foot types during barefoot walking trials in 92 subjects. The Foot Posture Index was adopted to classify foot type and the “emed” plantar pressure system was used to calculate plantar pressures for the medial heel, lateral heel, midfoot, 1st, 2nd, 3rd, 4th and 5th MPTJ’s, the hallux, 2nd toe, and the 3rd, 4th and 5th toes.
The greatest variances were seen in forefoot pressures between pes planus and pes cavus feet, and each foot posture classification showed its own unique plantar pressure characteristics. There were also significantly lower peak pressures at the 4th and 5th MTPJ's in the planus foot group compared to the normal and cavus foot groups.
The authors concluded that foot posture does influence plantar pressures and “each foot posture classification displays unique plantar pressure characteristics”.
Feet, Orthoses and Lower Back Pain
Two new studies have recently addressed the relationship between foot position and lower back pain (LBP). The Journal of Electromyography and Kinesiology printed a paper investigating “muscle activity and kinetics of lower limbs during walking in pronated individuals with and without low back pain"; and The Foot published a review titled “Foot orthotics for low back pain: The state of our understanding and recommendations for future research”.
The first paper found an association between pronated feet plus LBP with less ankle inversion and knee flexion, higher knee and hip internal rotation, higher muscle activity, less energy absorption at the ankle and reduced positive power at the knee when compared to a normal control group and a group who exhibited pronated feet without LBP. The authors concluded that strengthening knee extensors is important for LBP patients with excessive foot pronation.
The second paper reviewed “the biomechanical mechanisms underlying the effectiveness of foot orthotic treatment and the current state of knowledge regarding the clinical use of foot orthotics to treat / prevent the occurrence of low back pain”. The authors concluded that there is a lack of high quality RCTs but there is a wide research base addressing biomechanical mechanisms and clinical outcomes in relation to foot orthoses. Importantly, this review has highlighted some promising pilot studies and ongoing large-scale RCTs which are addressing the effects of foot orthoses on chronic LBP.
Achilles Tendinopathy: Biomechanical Characteristics
A systematic review published recently in Gait and Posture has provided a list of lower limb biomechanical characteristics for individuals with Achilles Tendinopathy (AT).
The study sought to update a previous systematic review which examined lower-limb gait biomechanics in patients with AT. 14 studies were selected which included 836 participants.
The review concluded that AT is a topic “rich in quantity but generally weak in quality”. However, 18 new gait characteristics were identified for AT. For runners, reduced temporospatial characteristics, reduced gluteal muscle activity and size reductions in gait speed, stride length and step length were all identified. Additionally, greater ankle eversion, time to maximum pronation, calcaneal inversion and ankle and hip joint moments were all established for patients with AT. Those patients also demonstrated differences in amplitude and timing of several lower-limb muscles, particularly reductions in the onset of activity and duration of activation in the Gluteus Medius.
High powered prospective studies are recommended to determine causality for future research.