Autonomous field measurements of CO2 in the atmospheric column with the miniaturized laser heterodyne radiometer (Mini-LHR).

We present column CO2 measurements taken by the passive miniaturized laser heterodyne radiometer (Mini-LHR) at 1611.51 nm at the Mauna Loa Observatory in Hawaii. The Mini-LHR was operated autonomously, during the month of May 2013 at this site, working in tandem with an AERONET sun photometer that measures aerosol optical depth at 15-min intervals during daylight hours. Laser heterodyne radiometry has been used since the 1970s to measure atmospheric gases such as ozone, water vapor, methane, ammonia, chlorine monoxide, and nitrous oxide. This iteration of the technology utilizes distributed feedback lasers to produce a low-cost, small, portable sensor that has potential for global deployment. Applications of this instrument include supplementation of existing monitoring networks to provide denser global coverage, providing validation for larger satellite missions, and targeting regions of carbon flux uncertainty. Also presented here are preliminary retrieval analysis and the performance analysis that demonstrate that the Mini-LHR responds extremely well to changes in the atmospheric absorption.

Harmful cleats of football boots: a biomechanical evaluation.

BACKGROUND: Football players wear boots of varying cleat designs with some preferring the bladed cleats while others opting for the conventional studded cleats. The current study compares biomechanically the boots with differing cleat designs and their effect on feet, if any. METHODS: Twenty-nine healthy male volunteers were recruited from amateur football teams. They were asked to perform three trials each of two activities: a straight run and a run cutting at a 60° angle wearing bladed and studded Adidas®-F series boots on artificial turf. Plantar pressure values were recorded using the Pedar®-X in-shoe pressure measuring device. Peak pressure and pressure-time integral were analysed over 11 clinically relevant areas under the foot. RESULTS: While the in-shoe pressure and pressure-time integral were higher under the medial half of the foot with studded boots, they were higher under the lateral half of the foot with the bladed design. CONCLUSIONS: The studded boots can be considered safer as the pressure distribution across the foot and the pattern of centre of pressure progression mimicked the normal motif, whereas the bladed boots could potentially be deemed relatively more harmful due to the unnatural increased loading under the lateral half of the foot, predisposing the foot to injuries.

The influence of shoe sole's varying thickness on lower limb muscle activity.

BACKGROUND: The lateral ligament injury of the ankle is acknowledged to be the most common ankle injury sustained in sport. Increased peroneus longus muscle contraction in the shod population has already been documented. This study aimed to quantify the effect of shoe sole's varying thickness on peroneus longus muscle activity. METHODS: Electromyographic recordings of the peroneus longus muscle activity following unanticipated inversion of the foot from 0° to 20° in a two-footplate tilting platform were collected from 38 healthy participants. The four test conditions were: barefoot, standard shoe, and shoes with 2.5 cm and 5 cm sole adaptation respectively. RESULTS: Compared to the barefoot condition, there is an increase in the magnitude of muscle contraction on wearing shoes, which further increases with thickening shoe soles. The peroneus longus was responding earlier in the shod conditions when compared to the barefoot, although the results were variable within the three shod conditions. CONCLUSION: Footwear with increasing shoe sole thickness evokes a correspondingly stronger protective eversion response from the peroneus longus to counter the increasing moment at the ankle-subtalar joint complex following sudden foot inversion. Hence, fashion footwear with thicker sole is likely to increase the risk of lateral ligament injury of the ankle when such protective response is overwhelmed. Similarly, the clinicians need to be cautious regarding the amount of shoe raise that they could provide for patients with limb length discrepancy without any detrimental untoward side effects.

Repeatability of the Pedar-X in-shoe pressure measuring system.

BACKGROUND: The Pedar-X is one of the newer versions of in-shoe pressure measuring devices and the current study aimed to assess the repeatability of this device. METHODS: Twenty-seven healthy male volunteers were recruited and requested to walk on a 26-feet walkway wearing appropriate sized standardised off-the-shelf neutral running shoes (Donnay International). The Pedar-X insole was sandwiched between the foot and the shoe. Data were collected on two occasions, one week apart. Clinically relevant parameters studied were contact area, contact time in percentage roll over process, maximum force, pressure-time integral, force-time integral, peak pressure, mean force and mean area. RESULTS: Repeatability was analysed using the coefficient of variation. Of the 160 parameters considered, 93.1% revealed a coefficient of variation value of less than 25. Heel and the metatarsal head areas were the most repeatable. CONCLUSION: The Pedar-X in-shoe pressure measuring system is repeatable and as such can be used as a valuable tool in the assessment of in-shoe plantar pressure distribution.

The effects of off-the-shelf in-shoe heel inserts on forefoot plantar pressure.

Off-the-shelf heel inserts are used widely without adequate scientific information regarding their effects upon the forefoot. The aim of this study was to assess whether the use of in-shoe heel inserts affects the plantar pressure distribution under the forefoot. Thirty-five asymptomatic volunteers consented to participate. Six brands of off-the-shelf heel inserts were tested. Subjects walked along a 10 m walkway with no inserts and then with each pair of inserts, in a randomised order. The Pedar system was used to record in-shoe plantar pressure data. The results confirmed that heel inserts increased pressure under the metatarsal heads and altered the biomechanics of the foot even in asymptomatic subjects. The findings suggested that heel inserts should be used with caution especially in people predisposed to foot problems. The classification of these inserts as an over-the-counter product may need to be reviewed.

Off-the-shelf in-shoe heel inserts: does cost matter?

OBJECTIVE: A growing exercise culture has lead to an increase in the use of off-the-shelf heel inserts. While there are a variety of designs in a spectrum of cost ranges, probably the ease of availability and cost would mainly determine the choice of purchase. This study was designed to determine whether expensive designs provide better pressure attenuation under the heel than their less expensive counterparts. PARTICIPANTS AND DESIGN: Six brands of off-the-shelf heel inserts were tested. Selection of these was based purely on their availability in all sizes. Cost per pair ranged from 6 pounds sterling to 30 pounds sterling. Thirty-five asymptomatic subjects walked on a 10 m walkway, once with no inserts and once with each pair of inserts. The Pedar in-shoe system recorded a range of parameters under the heel. SETTING: Institute of Motion Analysis and Research, Ninewells Hospital and Medical School, University of Dundee. MAIN OUTCOME MEASURES: Evaluation of plantar pressure parameters under the heel. RESULTS: All inserts reduced peak pressure under the heel. Maximum force and pressure-time integral also decreased. Contact time generally increased with the use of inserts. Values of contact area with and without inserts were comparable. CONCLUSIONS: No significant differences were observed under the heel between the pressure attenuation properties of the lowest-priced and the most expensive designs, and hence the less expensive inserts can be considered as good as the expensive brands. However, the endurance power of these inserts may differ and this should be evaluated.

The effect of varying footwear configurations on the peroneus longus muscle function following inversion.

BACKGROUND: The ankle is one of the most commonly injured joints with inversion injury affecting its lateral ligament complex being the commonest of all. Shoes are one of the known risk factors for such an injury. OBJECTIVE: This study seeks to examine the impact of varying shoe configurations on the protective function of the peroneus longus muscle during unanticipated foot inversion. METHODS: The peak amplitude, latency and post-peak average amplitude of the ipsilateral peroneus longus muscle were recorded by surface electromyography following unanticipated inversion of the feet of 35 subjects in a two-footplate tilting platform from 0° to 20°. The test conditions were barefoot, standard training shoe, shoe with a sole flare, and an above the ankle laced boot. RESULTS: Analysis revealed significant differences in peak muscle contraction between shod and unshod conditions. The standard shoe and the flared sole design showed greater statistically significant differences from the unshod condition, than the boot. The muscle was responding earlier in the shod conditions compared to the barefoot. The post-peak average amplitude with the standard shoe and the flared sole shoe were significantly different from the barefoot condition. CONCLUSION: Albeit no marked differences could be demonstrated between the tested shoes, the inherent construct of the laced boot probably attempts to protect the ankle-subtalar joint complex evidenced by evoking a less strong peroneus longus muscle's protective response.

A new scoring system for the evaluation of clubfoot: the IMAR-Clubfoot scale.

BACKGROUND: Recently much interest has been shown regarding the biomechanical techniques for the assessment of clubfoot but as yet their specific role in such an endeavour is unclear. Several scoring systems have been designed but none have been adopted as a standard. The ideal system should be simple, modular, reliable, repeatable and be able to assess functional deformity objectively. OBJECTIVE: This study was aimed to develop a comprehensive scoring system and to demonstrate the potential of such an assessment tool in evaluating clubfoot. METHODS: A new innovative scoring system, the IMAR-Clubfoot scale, was designed, which incorporated clinical and biomechanical data. Clinical assessment was performed using a questionnaire and standard clinical criteria while the biomechanical evaluation was undertaken using the Podotrack, the optical dynamic pedobarograph and the GAITRite systems. Thirteen children (16 clubfeet) were recruited for assessment using the IMAR-Clubfoot scale. RESULTS: The model can detect abnormalities related to talipes equinovarus and quantify them objectively. The results also emphasise the need for such a comprehensive system, which combines clinical and biomechanical data as there was no statistical correlation between these data. CONCLUSION: The scoring system would be helpful in assessing the deformity, deciding upon appropriate management and objectively defining the success/failure of treatment at patient follow-up.

Foot pressure in clubfoot--the development of an objective assessment tool.

BACKGROUND: There are no universal criteria for the assessment of clubfoot. The ideal method should assess functional deformity reliably and objectively. Biomechanical techniques have also been suggested but their role remains undefined. OBJECTIVE: This study aimed to assess surgically corrected clubfeet by biomechanical means with the intention to develop certain ratios to aid in objective assessment. METHODS: Thirteen children (16 feet) with idiopathic clubfoot, who had previously undergone surgery (lateral-posteromedial release), were reviewed. Various clinical measurements were collected and symptoms assessed using a specially designed questionnaire. Biomechanical (foot pressure) parameters were obtained using two systems: Podotrack and Dynamic Pedobarograph. RESULTS: The results showed that foot pressure data were able to demonstrate abnormalities in foot posture and pressure distribution, which could objectively identify clubfoot deformities. In particular, ratios were calculated, which could be used to determine severity and monitor progression. CONCLUSION: This study suggests that foot pressure analysis should be routinely used in the assessment of clubfoot. The ratios calculated would be of immense help to the clinicians in monitoring the success of treatment and for early prediction of relapse in patients treated for clubfoot.