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.

Differences in foot pressures between Caucasians and Indians.

BACKGROUND: Indians are the largest single ethnic minority group in the United Kingdom and form more than one million of the current population. No studies have investigated foot pressure differences between Caucasians and Indians. OBJECTIVE: The aim of our study was to investigate the in-shoe pressure differences in Caucasians and Indians using the Pedar(®)-m (Novel GmbH, Germany). METHODS: The study included 12 Caucasians and 21 Indians. Peak pressure (PP), contact area (CA), contact time (CT), pressure-time integral (PTI), force-time integral (FTI), instant of peak pressure (IPP), maximum force (MaxF) and mean force (MeanF) were recorded. RESULTS: Caucasians had higher significant PP compared to Indians under the heel (293 kPa vs. 251 kPa; P<0.001), 1st metatarsal head (294 kPa vs. 233 kPa; P=0.01), 2nd metatarsal head (266 kPa vs. 236 kPa; P=0.03), 3rd metatarsal head (254 kPa vs. 223 kPa; P=0.04), and the 5th metatarsal head (168 kPa vs. 133 kPa; P=0.04). There was no significant difference in the contact area between the two race groups. The PTI was statistically significantly higher in Caucasians in the region of the 1st metatarsal head (79 kPas vs. 62 kPas; P=0.03) and 5th metatarsal head (58 kPas vs. 44 kPas; P=0.03). There were no significant differences among CT, FTI, IPP, MaxF and MeanF among them. CONCLUSION: The PP under the heel, 1st, 2nd, 3rd and 5th metatarsal heads and the PTI under the 1st and 5th metatarsal heads in Caucasians is higher than in Indians. There is no difference in the CA.

Foot pressure differences in men and women.

BACKGROUND: Women and men are anatomically and physiologically different in a number of ways. Anthropometric studies have shown considerable differences in the foot bones of both genders. These differences could potentially mean different foot pressures in men and women. OBJECTIVE: The aim of our study was to investigate any potential foot pressure differences between males and females using the Pedar-M (Novel gmbh, Germany) in-shoe foot pressure measurement system. METHODS: Twenty-eight subjects (16 females and 12 males) were recruited. Peak pressure, contact area, contact time, pressure-time integral, force-time integral, instant of peak pressure, maximum force and mean force were recorded and subsequently analysed. RESULTS: In males, contact area was significantly larger in all regions of the foot compared with females. There were no significant between gender differences in peak pressure, contact time, pressure-time integral and instant of peak pressure. Force-time integral was significantly greater in males than females under the 1st, 3rd, and 4th metatarsal heads. Maximum force was also significantly higher in males under the heel, 1st and 3rd metatarsal heads. Mean force was greater in males under the 3rd metatarsal head. CONCLUSION: There were no peak pressure differences; however the contact area of the male foot was larger than that in females.

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 wearing an Ankle Stabilizing Orthosis (ASO) Ankle Brace on ankle joints kinetics and kinematics during a basketball rebounding task.

Following an ankle injury, athletes sometimes brace the injured ankle in hopes of minimizing the likelihood of suffering a recurring injury. This study aims to evaluate the effects of wearing an Ankle Stabilizing Orthosis (ASO) ankle brace unilaterally on the dominant side on bilateral ankle joint kinetics and kinematics and peroneus longus EMG activity. Since a significant proportion of ankle injuries in basketball occur during rebounding, data was collected during a simulated rebounding task. Rebounding is defined as the act of retrieving a missed shot attempt. Subjects oftentimes jump vertically to acquire the basketball as it rebounds from the backboard or rim. Sixteen subjects participated in the study (11 males, 5 females; mean age = 26.94 years, SD = 5.32; mean height 1.72 m, SD = 0.08; mean weight 73.95 kg, SD = 13.68). Participants completed the rebounding task in braced (ASO) and unbraced (UB) conditions. Ankle and foot inversion angles, ankle inversion moments and peroneus longus EMG activity were recorded and analysed to determine the effects of wearing an ankle brace unilaterally. In the dominant limb, when compared to UB, ASO reduced ankle and foot inversion, and increased ankle inversion moments. No significant differences were observed in peroneus longus EMG activity. In the non-dominant limb, no significant differences were observed for any of the parameters. These results suggest that wearing an ASO ankle brace on the dominant ankle reduces maximum ankle and foot inversion angles without posing an increased risk to the unbraced leg. However, the increased ankle inversion moments in the braced ankle suggest that there are adjustments regarding force distribution, perhaps due to the restricted range of motion.

Comparison of 3 ankle braces in reducing ankle inversion in a basketball rebounding task.

Lateral ankle injury incidence rates are very high in the sport of basketball, with a significant proportion occurring during rebounding. Ankle braces are often used as preventative and rehabilitative techniques in the hope of minimizing the likelihood of experiencing excessive ankle inversion. This study aims to evaluate the effect of different ankle braces in preventing ankle inversion during a basketball rebounding task. Sixteen subjects participated in the study (11 males, 5 females; mean age = 26.94 years, SD = 5.32; mean height 1.72 m, SD = 0.08; mean weight 73.95 kg, SD = 13.68). Participants performed a simulated rebounding task in multiple braced conditions: unbraced (UB), Ossur Formfit (OF), Talarmade Ankleguard Air/Gel Stirrup (TAG) and Bauerfeind Malleoloc (BF). Ankle and foot inversion angles, ankle inversion moments and peroneus longus EMG activity were recorded and analysed to determine the effectiveness of each condition to resist inversion. All braced conditions reduced ankle and foot inversion angles compared to UB. In the non-dominant limb, OF showed reduced maximum ankle inversion compared to BF (non-dominant mean difference = 0.630°, p < 0.001) and reduced foot inversion compared to TAG (non-dominant mean difference = 0.966°, p = 0.035). Compared to UB, OF and TAG increased ankle inversion moments in the dominant ankle and showed decreases in the non-dominant ankle. BF reduced mean peak peroneus longus EMG activity compared to all other trials. Whilst statistically significant differences that were demonstrated between several braced conditions are relatively small, they are clinically significant knowing that the maximum barefoot inversion whilst standing is less than 17 degrees.

Normal pressure values and repeatability of the Emed ST4 system.

The aims of this study were to assess the repeatability of the Emed ST4 system and identify the range of pressure values observed in the normal foot. Fifty-three healthy subjects, 17 females (32%) and 36 males (68%), were recruited. Measurements were performed on two occasions approximately 12 days apart. Peak pressure (PP), contact area (CA), contact time (CT), pressure-time integral (PTI), force-time integral (FTI) and instant of peak pressure (IPP) were recorded. The coefficient of repeatability (CR) was less than 16.9% for all 122 parameters considered. The highest areas of PP were found under the second and third metatarsal heads, with mean (S.D.) equal to 361 kPa (104) and 330 kPa (84), respectively, followed by the great toe 321 kPa (141) and heel 313 kPa (77). CA was highest under the heel at 35 cm(2) (5). The percentage CT was in the range 75-85% under the metatarsal heads, and 70% under the hallux. PTI was highest under metatarsal heads one to three and hallux. FTI was highest under the heel. Emed ST4 system was found to be repeatable. The ranges of the parameters documented can be applied in orthopaedic clinics as part of the assessment of pathological conditions.

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.

Do you get value for money when you buy an expensive pair of running shoes?

OBJECTIVE: This investigation aims to determine if more expensive running shoes provide better cushioning of plantar pressure and are more comfortable than low-cost alternatives from the same brand. METHODS: Three pairs of running shoes were purchased from three different manufacturers at three different price ranges: low (40-45 pounds), medium (60-65 pounds) and high (70-75 pounds). Plantar pressure was recorded with the Pedar in-shoe pressure measurement system. Comfort was assessed with a 100 mm visual analogue scale. A follow-on study was conducted to ascertain if shoe cushioning and comfort were comparable to walking while running on a treadmill. Forty-three and 9 male subjects participated in the main and follow-on studies, respectively. The main outcome measure was the evaluation of plantar pressure and comfort. RESULTS: Plantar pressure measurements were recorded from under the heel, across the forefoot and under the great toe. Differences in plantar pressure were recorded between models and between brands in relation to cost. Shoe performance was comparable between walking and running trials on a treadmill. No significant difference was observed between shoes and test occasions in terms of comfort. CONCLUSIONS: Low- and medium-cost running shoes in each of the three brands tested provided the same (if not better) cushioning of plantar pressure as high-cost running shoes. Cushioning was comparable when walking and running on a treadmill. Comfort is a subjective sensation based on individual preferences and was not related to either the distribution of plantar pressure or cost.

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 Pedar in-shoe system: repeatability and normal pressure values.

The Pedar system is one of the most commonly used systems for in-shoe pressure measurement. Good repeatability is necessary to ensure the consistency of measurements on which clinical judgements are based. In addition, there is a need to establish a range of normal in-shoe pressure values, which will help to identify abnormalities. The aim of this study was to assess the repeatability of the Pedar system and determine the pressure values in normal subjects. Fifty-three subjects, 17 females (32%) and 36 males (68%), were recruited and measurements were performed twice with an average gap of 12 days (range 1-32 days) using only one brand of standardised running shoes (Donnay International). Peak pressure (PP), contact area (CA), contact time (CT), pressure-time integral (PTI), force-time integral (FTI) and instant of peak pressure (IPP) were calculated. The coefficient of repeatability (CR), expressed as a percentage of the mean, was no greater than 15.3% for all 122 parameters considered. The highest PP areas were under the great toe, with mean (S.D.) equal to 280.4 (83.0) kPa and heel 264.3 (44.1) kPa, followed by the first 248 (70.1) kPa, second 246.5 (48.3) kPa, and third 224.7 (50.4) kPa metatarsal heads. The CA was highest under the heel at 41.54 cm(2). The CT of the metatarsals was 77% to 87% of the total CT while that of the hallux was 75%. The PTI and FTI were highest under the heel. We concluded that the Pedar system was repeatable. The normal pressure values identified can therefore be used to provide a reference range in clinical practice using this specific type of footwear.

Effect of Vitamin K on Vascular Health and Physical Function in Older People with Vascular Disease--A Randomised Controlled Trial.

BACKGROUND AND AIMS: Vitamin K insufficiency is common and linked to an increased risk of cardiovascular disease and osteoporotic fractures. The aim of this study was to examine whether daily supplementation with oral vitamin K could improve vascular health and physical function in older people with established vascular disease. METHODS AND RESULTS: A double blind, randomised, placebo-controlled trial. Participants aged ≤ 70 years with a history of vascular disease were randomised to receive 6 months of daily oral 100mcg vitamin K2 (MK7 subtype) or matching placebo with outcomes measured at 0, 3 and 6 months. The primary outcome was between-group difference in endothelial function assessed using flow-mediated dilatation of the brachial artery at 6 months. Secondary outcomes included carotid-radial pulse wave velocity, augmentation index, blood pressure, carotid intima-media thickness, C-reactive protein, B-type natriuretic peptide, cholesterol and desphospho-uncarboxylated matrix Gla protein levels. Handgrip strength and the Short Physical Performance Battery assessed physical function, while postural sway was measured using a 3-dimensional force platform. RESULTS: 80 participants were randomised, mean age 77 (SD 5) years; 44/80 were male. Vitamin K levels rose in the intervention arm compared to placebo (+48 pg/ml vs -6 pg/ml, p=0.03) at 6 months. Desphospho-uncarboxylated Matrix Gla protein levels fell in the intervention group compared to placebo at 6 months (-130 [SD 117] pmol/L vs +13 [SD 180] pmol/L, p<0.001). No change was seen in endothelial function (between group difference -0.3% [95%CI -1.3 to 0.8], p=0.62). A modest, non-significant improvement in pulse wave velocity was seen in the vitamin K group (-0.8m/s [95%CI -1.8 to 0.3], p=0.15) while all other vascular and physical function outcomes unchanged. CONCLUSIONS: Six months of vitamin K2 supplementation did not improve markers of vascular health or physical function in older patients with vascular disease.

Footwear in rock climbing: Current practice.

BACKGROUND: Many rock climbers wear ill-fitting and excessively tight footwear during activity. However, there is insufficient evidence of the extent or harms of this practice. OBJECTIVES: To investigate footwear use in rock climbers with a focus on issues surrounding fit. METHODS: A cross-sectional study with active rock climbers of over one year of experience completing a survey on their activity and footwear. Additionally, the authors quantified foot and shoe lengths and sizes alongside demographic data. RESULTS: Ill-fitting and excessively tight footwear was found in 55 out of 56 rock climbers. Foot pain during activity was also commonplace in 91% of the climbers. A mean size reduction of almost 4 UK shoe sizes was found between the climbers' street shoe size and that of their climbing footwear using a calibrated foot/shoe ruler. There is an unfortunate association of climbers of higher abilities seeking a tighter shoe fit (p<0.001). CONCLUSION: With the elucidation of footwear use amongst rock climbers, further investigation may aim to quantify its impact and seek a solution balancing climbing performance while mitigating foot injury.

Assessment of talipes equinovarus treated by Ponseti technique: three-year preliminary report.

BACKGROUND: The Ponseti method has become increasingly popular in the treatment of congenital talipes equinovarus (CTEV). Current methods of assessment focus on clinical, functional and radiological outcomes which are subjective and often difficult to repeat. However, integration of biomechanical evaluation can provide objective and quantifiable analysis. This study aims to evaluate the treatment outcome of CTEV patients on the basis of long-term clinical, functional and biomechanical assessment. METHODS: Following treatment, five children with CTEV were reviewed annually for the period 2008-2010. Clinical and functional outcomes were graded using parental questionnaires and clinical examination. Biomechanical parameters were evaluated using digital foot pressure studies. RESULTS: The study group recorded good clinical and functional outcomes. However, biomechanical studies have been able to identify subtle abnormalities that would be unapparent otherwise on clinical examination. CONCLUSIONS: It is recommended that biomechanical assessment be integrated into the overall evaluation of the outcome of CTEV after treatment.

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.

Objective assessment of the alterations in wrist mobility with the fastrak(®) system following dorsal capsulodesis.

The treatment for scapholunate dissociation is challenging and its management is varied depending on type, severity and duration of injury, and surgeon's preferred technique. This study aimed to objectively assess the variations in the range and patterns of wrist movements using the Fastrak(®) system in patients having undergone Blatt's dorsal capsulodesis (BDC). The wrist movements were successively measured between the operated and unoperated wrists, while the patients performed set tasks. Seventeen patients agreed to participate in the study. Following BDC the mean flexion loss was 23° (range 10°-38°). However, functional tasks revealed that the BDC did not adversely affect the function of the operated wrist. This novel study demonstrates objectively the functional restrictions that patients are likely to experience postoperatively following BDC. It would be interesting to note the pattern of wrist motion using the Fastrak(®) system in various other clinical settings.

Adapting the Fastrak system for three-dimensional measurement of the motion of the wrist.

The Polhemus Fastrak short-range miniature transmitter and mini-receivers allow wrist motion to be measured continually in three dimensions, registering patterns of motion, which until now were difficult to quantify. The current study aimed to determine the applicability and repeatability of the Fastrak system when assessing wrist movements during a set protocol of activities. The device was found to be easy to use and repeatable; the Fastrak system showed a mean error of up to 3 degrees in all movements tested. Its assessment of range of motion correlated with the results in the literature. The Fastrakv system was suitable for continuous registration of movements during the performance of set tasks in either of the wrists. It has the potential to be used for documentation of wrist motion in clinics for various pathologies and for assessing outcomes in wrist surgeries.

Parametric oscillator: HF oscillator-amplifier pumped CdSe parametric oscillator tunable from 14.1 microm to 16.4 microm.

A singly resonant CdSe parametric oscillator with tunable output from 14.1 microm to 16.4 microm is described. The oscillator, pumped by the 2.87-microm line from an HF oscillator-amplifier, is resonant on the signal near 3.5 microm and has produced idler outputs of 100 microJ at 16 microm. Bandwidths varied over the tuning range from 9 cm(-1) to 1.8 cm(-1). Techniques for obtaining a highly coherent HF laser pump beam are presented. The uniform beam from the gain-saturated amplifier allows the use of Fresnel diffraction theory to produce a nearly uniform pump beam at the oscillator cavity.