Effects of Gradient and Speed on Uphill Running Gait Variability.

BACKGROUND: The aim of this study was to investigate the effects of gradient and speed on running variability (RV) and local dynamic stability (LDS) during uphill running. HYPOTHESES: (1) Both gradient and speed increase metabolic effort, in terms of heart rate (HR) and perceived exertion (CR10), in line with the contemporary literature, and (2) gradient increases RV and impairs LDS. STUDY DESIGN: "Crossover" observational design. LEVEL OF EVIDENCE: Level 3. METHODS: A total of 25 runners completed 10-minute running trials in 3 different conditions and in a randomized order: gradient at 0% (0CON), 2% (2CON), and 2% at isoefficiency speed (2IES). 0CON and 2CON speeds were calculated as the "best 10-km race performance" minus 1 km·h-1, whereas 2IES speed was adjusted to induce the same metabolic expenditure as 0CON. HR and perceived exertion as well as running kinematic variables were collected across all trials and conditions. Running variability was calculated as the standard deviation of the mean stride-to-stride intervals over 100 strides, while LDS was expressed by the Lyapunov exponent (LyE) determined on running cycle time over different running conditions. RESULTS: Increases in HR and CR10 were observed between 0CON and 2CON (P < 0.001) and between 2IES and 2CON (P < 0.01). Higher RV was found in 2CON compared with 0CON and 2IES (both P < 0.001). Finally, the largest LyE was observed in 2IES compared with 0CON and 2CON (P = 0.02 and P = 0.01, respectively). CONCLUSION: Whereas RV seems to be dependent more on metabolic effort, LDS is affected by gradient to a greater extent. CLINICAL RELEVANCE: Running variability could be used to monitor external training load in marathon runners.

Static Balance Digital Endpoints with Mon4t: Smartphone Sensors vs. Force Plate.

Static balance tests are conducted in various clinics for diagnosis and treatment adjustment. As a result of population aging, the accessibility of these tests should be increased, in the clinic, and for remote patient examination. A number of publications have already conducted static balance evaluations using the sensors embedded in a smartphone. This study focuses on the applicability of using smartphone-based balance assessment on a large scale while considering ease of use, safety, and reliability. The Mon4t® app was used to acquire the postural motion using different smartphone devices, different smartphone locations, and various standing postures. The signals derived from the app were compared to the center of pressure displacement derived from a force plate. The results showed moderate to high agreement between the two methods, particularly at the tandem stance (0.69 ≤ r ≤ 0.91). Preliminary data collection was conducted on three healthy participants, followed by 50 additional healthy volunteers, aged 65+. The results demonstrated that the Mon4t app can serve as an accessible and inexpensive static balance assessment tool, both in clinical settings and for remote patient monitoring, which is key for enabling telehealth.

Meniscal extrusion under increasing varus in stress patients with a medial meniscus posterior root-tear.

Posterior root-tear of the medial meniscus and accompanied meniscal extrusion can lead to functional loss of the meniscus. The aim of this study is to assess medial meniscus extrusion at increasing varus forces utilizing magnetic resonance imaging (MRI), in order to evaluate the contribution of the adduction moment of the knee during gait. We prospectively enrolled 19 patients (38 knees). Patients underwent gait analysis testing to calculate adduction moment, followed by an MRI at rest and with increasing varus forces according to the patient's specific adduction moment. Meniscal extrusion and root gap at increasing varus forces were measured and compared. Functional outcomes and their association to meniscal extrusion was analyzed. We found the average meniscal extrusion at rest, 100% and 150% applied varus force for the control group to be 1.7mm, 1.7mm and 1.9mm, respectively; and for the index group average meniscal extrusion was 5.3mm, 6.4mm and 6.8mm, respectively. Meniscal extrusion increase from rest to 100% varus force was significantly higher in the index group (p=0.0002). Further meniscal extrusion and root gap increase from 100% varus force to 150% varus force did not show a statistically significant difference (p=0.39). The association between greater increase of meniscal extrusion with varus force and WOMAC scores was not statistically significant. In conclusion this study defines the contribution of the varus force component of the adduction moment to meniscal extrusion, in patients with a medial meniscus posterior root-tear.

Personalized multicomponent exercise programs using smartphone technology among older people: protocol for a randomized controlled trial.

BACKGROUND: Optimal application of the recently updated World Health Organization (WHO) guidelines for exercise in advanced age necessitates an accurate adjustment for the age-related increasing variability in biological age and fitness levels, alongside detailed recommendations across a range of motor fitness components, including balance, strength, and flexibility. We previously developed and validated a novel tool, designed to both remotely assess these fitness components, and subsequently deliver a personalized exercise program via smartphone. We describe the design of a prospective randomized control trial, comparing the effectiveness of the remotely delivered personalized multicomponent exercise program to either WHO exercise guidelines or no intervention. METHODS: Participants (n = 300) are community dwelling, healthy, functionally independent, cognitively intact volunteers aged ≥65 at low risk for serious fall injuries, assigned using permuted block randomization (age/gender) to intervention, active-control, or control group. The intervention is an 8-week program including individually tailored exercises for upper/lower body, flexibility, strength, and balance (dynamic, static, vestibular); active-controls receive exercising counselling according to WHO guidelines; controls receive no guidance. Primary outcome is participant fitness level, operationalized as 42 digital markers generated from 10 motor fitness measures (balance, strength, flexibility); measured at baseline, mid-trial (4-weeks), trial-end (8-weeks), and follow-up (12-weeks). Target sample size is 300 participants to provide 99% power for moderate and high effect sizes (Cohen's f = 0.25, 0.40 respectively). DISCUSSION: The study will help understand the value of individualized motor fitness assessment used to generate personalized multicomponent exercise programs, delivered remotely among older adults. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04181983.

Effect of Mini-invasive Floating Metatarsal Osteotomy on Plantar Pressure in Patients With Diabetic Plantar Metatarsal Head Ulcers.

BACKGROUND: Distal metatarsal osteotomy has been used to alleviate plantar pressure caused by anatomic deformities. This study's purpose was to examine the effect of minimally invasive floating metatarsal osteotomy on plantar pressure in patients with diabetic metatarsal head ulcers. METHODS: We performed a retrospective case series of prospectively collected data on 32 patients with diabetes complicated by plantar metatarsal head ulcers without ischemia. Peak plantar pressure and pressure time integrals were examined using the Tekscan MatScan prior to surgery and 6 months following minimally invasive floating metatarsal osteotomy. Patients were followed for complications for at least 1 year. RESULTS: Peak plantar pressure at the level of the osteotomized metatarsal head decreased from 338.1 to 225.4 kPa (P < .0001). The pressure time integral decreased from 82.4 to 65.0 kPa·s (P < .0001). All ulcers healed within a mean of 3.7 ± 4.2 weeks. There was 1 recurrence (under a hypertrophic callus of the osteotomy) during a median follow-up of 18.3 months (range, 12.2-27). Following surgery, adjacent sites showed increased plantar pressure and 4 patients developed transfer lesions (under an adjacent metatarsal head); all were managed successfully. There was 1 serious adverse event related to surgery (operative site infection) that resolved with antibiotics. CONCLUSION: This study showed that the minimally invasive floating metatarsal osteotomy successfully reduced local plantar pressure and that the method was safe and effective, both in treatment and prevention of recurrence. LEVEL OF EVIDENCE: Level III, retrospective case series of prospectively collected data.

Symmetries in Muscle Torque and Landing Kinematics Are Associated With Maintenance of Sports Participation at 5 to 10 Years After ACL Reconstruction in Young Men.

BACKGROUND: Long-term maintenance of sports participation is important for young men undergoing anterior cruciate ligament (ACL) reconstruction. Identifying biomechanical characteristics in patients who achieve this goal can assist in elaborating rehabilitation programs and in identifying successful recovery, but this has rarely been investigated. PURPOSE: To test the association between maintenance of sports participation at 5 to 10 years after ACL reconstruction and measures of force production and landing biomechanics in men. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: A total of 30 men who underwent isolated ACL reconstruction were examined. At 5- to 10-year follow-up, associations were tested between reported outcomes of sports maintenance and objective biomechanical measures. The biomechanical tests included isokinetic knee torque and lower limb kinetics and kinematics during landing tasks. Measurements for each limb were conducted separately, and side-to-side symmetry indices (SI) were calculated. Subgroups included SI greater than +10% (ie, extreme positive), SI lower than -10% (ie, extreme negative), and SI between -10% and +10% (ie, symmetric). RESULTS: At follow-up, concentric knee torque in the operated limb correlated with Tegner and Marx scores (r = 0.42-0.47; P ≤ .05). Regarding the SI of knee torque, the highest Tegner, Marx, and KOOS (Knee injury and Osteoarthritis Outcome Score) results were associated with symmetry, as opposed to patients with extreme positive or extreme negative SIs (P < .05). As for landing kinematics, Tegner score negatively correlated with knee range of motion (ROM) in the operated limb (r = -0.38; P ≤ .05). With regard to SI, hip and knee ROM correlated with Tegner, IKDC, and KOOS scores (r = 0.41-0.51; P ≤ .05). Specifically, the highest sports participation levels were associated with achieving symmetric hip and knee ROM but also with extreme positive SIs, as opposed to patients with extreme negative SIs (P < .03), indicating substantially higher ROM in the uninjured limb as compared with the operated limb. CONCLUSION: At 5 to 10 years after ACL reconstruction, maintenance of sports participation was associated with symmetric side-to-side concentric knee torque and with producing greater attenuation of hip and knee ROM during the drop jump landing in the operated limb. Therefore, eccentric load programs that can improve attenuation-phase kinematics during landing tasks may be valuable in addition to concentric training and may facilitate enhanced long-term outcomes.

The influence of single-leg landing direction on lower limbs biomechanics.

BACKGROUND: The purpose of this study was to investigate whether different directions of single-leg landing tasks would influence lower limbs joints biomechanics. METHODS: Using a controlled and experimental design, thirty physically active male subjects (age: 26.4±4.4 years; height: 180.5±3.7 cm; weight: 79.8:±4.4 kg), by dropping down from the top of a wooden box of 31 cm height, performed three one-leg landing tasks featured by different landing directions: frontward (FL), lateral (LL), and rotational (RL). The trunk and lower limbs` joints biomechanical responses were assessed through a laboratory setup consisting in a 6-camera motion capture system synchronized with force plates. A repeated measures one-way Analysis of Variance (ANOVA) was used to investigate the main effects of the landing directions on the lower limbs joints biomechanics during the main phases of interest of the landing tasks. RESULTS: The results indicated two major findings: 1) FL resulted in an advantageous active whole-body configuration; 2) the lower limbs' joints adopted different and specific energy absorption strategies between the landing tasks. CONCLUSIONS: This study indicates that the different landing tasks likely generate meaningful changes in in whole body biomechanics and specific lower limbs joints kinetic and kinematic responses. Such outcomes might be used by clinicians towards a practical approach in selecting either assessment modalities or exercise interventions.

Recent Ankle Injury, Sport Participation Level, and Tests of Proprioception.

OBJECTIVE: Assessing the effects of ankle injury and sport participation level on ankle proprioceptive sensitivity using a joint position reproduction (JPR) test and an inversion movement extent discrimination test. DESIGN: Cross-sectional. SETTING: Biomechanics lab. PARTICIPANTS: Forty-five student athletes ages 21-30 (mean = 24.8 y). MAIN OUTCOME MEASURES: Participants were tested for ankle inversion sensitivity using 2 devices; movement reproduction error was obtained from JPR in a non-weight-bearing (N-WB) state at 10° and 15° of inversion, and an ankle proprioceptive sensitivity score was obtained from the active movement extent discrimination apparatus (AMEDA), representing the ability to differentiate 5 inversion movement extents between 10.5° and 14.5°, with testing in both N-WB and weight-bearing (WB) states. RESULTS: For the 34 athletes with no ankle injury in the previous 12 months, the sensitivity scores achieved on the AMEDA were significantly higher (P < .01) than those for the 11 athletes with ankle injury, and the injury effect was significantly greater in WB (P = .01). In JPR testing, the 2.96° error of reproduction for athletes with no recent ankle injury was not significantly different from the 3.36° error for those with ankle injury (P = .46). Correlation of current sport participation level with JPR showed less error for higher-level performers (r = .49, P = .001) but no significant relationship to WB or N-WB AMEDA scores (both P > .61). WB AMEDA scores were significantly higher for athletes who had competed at a higher level of sport competition when <18 years old (r = -.57, P < .001). CONCLUSIONS: Previous ankle sprains affected proprioceptive scores on the WB AMEDA and N-WB AMEDA tests, indicating the sensitivity of the AMEDA movement discrimination test to the effects of ankle injury. The correlation between JPR scores and current level of sport participation suggests the sensitivity of the JPR test to current ankle use.

Isokinetic moment curve abnormalities are associated with articular knee lesions.

The aim of this study was to test whether lesions of the medial meniscus (MM) and of the anterior cruciate ligament (ACL) are associated with specific abnormalities of isokinetic moment curves (IMCs). Fifty-four young adults (20 active healthy people, and 34 patients with unilateral knee injuries) were assessed through knee extensor and flexor isokinetic tests at 60°/s. Qualitative IMC analysis was performed using a novel classification system which identified three distinct abnormal shapes. The chi-squared (χ2) test was used to determine the inter-individual and intra-individual differences between the groups. Quantitative IMC inter-group comparisons were performed by a one-way analysis of variance (ANOVA). Knees with MM and ACL lesions were consistently associated with IMC shape irregularities (p<0.001) and with abnormal quantitative scores (p<0.001). More specifically, knees with isolated ACL lesions and knees with combined ACL and MM lesions presented similar distribution of knee extensor and flexor IMC irregularities, which was not present in knees with isolated MM lesions. A possible association between specific knee pathologies and IMC irregularities was identified (all p<0.05). In conclusion, different knee pathologies may be associated with different qualitative IMCs, which could be used as an additional presentation tool in clinical settings.

The effect of eliminating leg length difference on plantar foot pressure distribution in patients wearing forefoot offloading shoe.

BACKGROUND AND PURPOSE: Elevated heel construction offloads the forefoot after surgery. However, side-to-side height difference alters limb kinetics, whereas leg-length equalizing-sole at non-operated side may have beneficial effects on foot loading. The purpose of this study was to characterize leg-length equalizing sole effect on bilateral plantar pressures when using heel-lift forefoot-offloading shoe. MATERIALS AND METHODS: Twenty men were tested walking. Plantar peak pressures (PP) and pressure-time integrals (PTI) in the forefoot-offloading shoe and in contralateral running shoe were compared between two conditions: one with- and the other without leg-length equalizing sole elevation at the running shoe. RESULTS: Adding leg-length equalizing sole to the running shoe resulted in the following changes in the forefoot-offloading shoe: increased lateral midfoot PP (8.7%, p=0.03), increased lateral midfoot (11.3%, p=0.05) and lateral metatarsals PTI (10.3%, p=0.04), and decreased medial and lateral heel PTI (>5%, p=0.02). These changes were non-significant when applying a Bonferroni correction. Changes in the running shoe were: increased medial midfoot (20.5%, p=0.03) and decreased 2nd and lateral metatarsals PP (23%, p<0.01). PTI increased in medial and lateral heel (>25%, p<0.01), medial midfoot (63.2%, p<0.01) and lateral midfoot (9.2%, p=0.04) and decreased in 2nd and lateral metatarsals (>24.5%, p<0.01). CONCLUSION: Leg-length equalizing sole at contralateral running shoe in subjects wearing forefoot-offloading shoe results in lateral load shift alongside heel pressure attenuation within the forefoot-offloading shoe, which is beneficial during first month after medial forefoot surgery. Reciprocal medial load-shift in the elevated running shoe itself should yet be considered when bilateral medial forefoot pathology is present.

Effects of a Program for Improving Biomechanical Characteristics During Walking and Running in Children Who Are Obese.

PURPOSE: To investigate the influence of a weight-reduction program with locomotion-emphasis on improving biomechanical characteristics of children who are obese (OW). METHODS: Ten children who are OW participated in a 6-month multidisciplinary childhood obesity management program (GRP1); another 10 children who are OW participated in the same multidisciplinary childhood obesity management program with additional locomotion-emphasis exercises for improving biomechanical characteristics (GRP2); and 10 control children who are OW with no intervention program. Outcomes were anthropometric measurements and temporal and foot pressure parameters. RESULTS: GRP2 had significantly improved foot pressure in the different walking/running speeds compared with GRP1. In the temporal parameters, pretests by speed by group interactions were significantly improved for GRP2 compared with GRP1. CONCLUSIONS: We found evidence to support beneficial effects of combined dietary and physical activity/locomotion-emphasis exercises on the movement characteristics of children who are OW.

Dynamic push-pull characteristics at three hand-reach envelopes: applications for the workplace.

Pushing and pulling are common tasks in the workplace. Overexertion injuries related to manual pushing and pulling are often observed, and therefore the understanding of work capacity is important for efficient and safe workstation design. The purpose of the present study was to describe workloads obtained during different reach envelopes during a seated push-pull task. Forty-five women performed an isokinetic push-pull sequence at two velocities. Strength, work and agonist/antagonist muscle ratio were calculated for the full range of motion (ROM). We then divided the ROM into three reach envelopes - neutral, medium, and maximum reach. The work capacity for each direction was determined and the reach envelope work data were compared. Push capability was best at medium reach envelope and pulling was best at maximum reach envelope. Push/pull strength ratio was approximately 1. A recommendation was made to avoid strenuous push-pull tasks at neutral reach envelopes.

Core stability training on lower limb balance strength.

This study aimed to assess the effects of core stability training on lower limbs' muscular asymmetries and imbalances in team sport. Twenty footballers were divided into two groups, either core stability or control group. Before each daily practice, core stability group (n = 10) performed a core stability training programme, while control group (n = 10) did a standard warm-up. The effects of the core stability training programme were assessed by performing isokinetic tests and single-leg countermovement jumps. Significant improvement was found for knee extensors peak torque at 3.14 rad · s(-1) (14%; P < 0.05), knee flexors peak torque at 1.05 and 3.14 rad · s(-1) (19% and 22% with P < 0.01 and P < 0.01, respectively) and peak torque flexors/extensors ratios at 1.05 and 3.14 rad · s(-1) (7.7% and 8.5% with P < 0.05 and P < 0.05, respectively) only in the core stability group. The jump tests showed a significant reduction in the strength asymmetries in core stability group (-71.4%; P = 0.02) while a concurrent increase was seen in the control group (33.3%; P < 0.05). This study provides practical evidence in combining core exercises for optimal lower limbs strength balance development in young soccer players.

Femoroacetabular impingement syndrome is associated with alterations in hindfoot mechanics: A three-dimensional gait analysis study.

BACKGROUND: Gait analysis studies in patients with femoroacetabular impingement syndrome focused until today on alterations in pelvic and hip mechanics, but distal articulations in this syndrome were not explored. Viewing the inter-relationships between foot and hip mechanics and the importance of the subtalar joint in load attenuation at heel strike and during forward propulsion thereafter, alterations in hindfoot mechanics in this syndrome may have clinical significance. METHODS: Three-dimensional gait kinematics were explored with emphasis on hindfoot mechanics in a group of 15 men with cam-type femoroacetabular impingement and compared to 15 healthy men. FINDINGS: Subjects with femoroacetabular impingement had decreased pelvic internal rotation (effect size=0.70) and hip abduction (effect size=0.86) at heel strike, and increased sagittal pelvic range of motion during the stance (effect size=0.81), compared to controls. At the hindfoot level, subjects with femoroacetabular impingement had inverted position at heel strike compared to neutral position in controls (effect size=0.89), and reduced maximum hindfoot eversion during the stance (effect size=0.72). Range of motion from heel strike to maximum eversion was not different between the groups (effect size=0.21). INTERPRETATION: Young adult men with cam-type femoroacetabular impingement syndrome present excessively inverted hindfoot at the moment of heel strike and reduction in maximum eversion during the stance phase. Viewing the deleterious effects of hindfoot malalignment on load attenuation during the stance, custom-designed insoles may be a consideration in this population and this should be investigated further.

Plantar Pressure Anomalies After Open Reduction With Internal Fixation of High-Grade Calcaneal Fractures.

BACKGROUND: Plantar pressure abnormalities after open reduction with internal fixation (ORIF) of intra-articular calcaneal fractures have been observed previously, but high-grade fractures were not selectively investigated and follow-up times were shorter than 2 years. The purpose of this study was to characterize plantar pressure anomalies in patients with exclusively high-grade calcaneal fractures after ORIF with a minimum 2 years of follow-up, and to test the association between plantar pressure distribution and the clinical outcome. METHODS: The orthopaedic registry was reviewed to identify patients with isolated high-grade calcaneal fractures (Sanders types III-IV) who were operated on and had a minimum 2 years of follow-up. Sixteen patients were evaluated. Mean age was 47 years and follow-up was between 2 and 6 years. The Pedar-Mobile system was used to measure 3 loading and 3 temporal variables and compare these between the operated and the uninjured limbs. RESULTS: Mean American Orthopaedic Foot and Ankle Society (AOFAS) score was 76 ± 7 at latest follow-up. Bohler's angle was 5 ± 8 degrees before surgery and 25 ± 7 degrees at latest follow-up. Stance was shorter in operated limbs (P = .001). Timing of the peak of pressure was delayed in operated limbs under the hallux and the second toe (P ≤ .03). Peak pressure, force time integral, and pressure time integral were increased under the lateral midfoot (P ≤ .03) and decreased under the second metatarsal (P ≤ .03). Force time integral was decreased under the first metatarsal (P = .02) and under the hallux and the lateral toes (P ≤ .05). Increased loading under the lateral midfoot and decreased loading under the lateral toes were correlated with poorer clinical outcome (r = -.53, P < .05, and r = .63, P < .01, respectively). CONCLUSIONS: Side-to-side plantar pressure mismatch persisted at more than 2 years after ORIF of high-grade calcaneal fractures performed via lateral approach, despite improvement of Bohler's angle. This was characterized by shortened stance phase, delayed timing of peak of pressure under the hallux and second toe, lateral load shift at the midfoot, and decreased toe pressures in operated limbs. Since loading abnormalities were correlated with the clinical outcome, modifications in treatment strategy that can improve foot loading may be desirable in these cases. LEVEL OF EVIDENCE: Level III, case control.

Arm-curl field test for older women: is it a measure of arm strength?

The facilitative effect of physical activity on age-related decline is well documented. Specifically, it has been found to reduce the risk of dependency. However, physical activity programs for older adults should be carefully designed so that improvements in all aspects of movement and physical capacities are achieved. This means that efficient fitness measurements should be made available for coaches and trainers. The arm-curl test is a common field test known for measuring the strength of upper extremities in older age. The objective of the current study was to determine to what extent this test indeed assesses arm strength as well as other fitness aspects such as arm muscle endurance or general endurance. Scores of the arm-curl test were compared with strength and endurance of elbow flexors measured by an isokinetic dynamometer and general endurance measured by a stress test in 48 independently functioning women (age 72.04 ± 6.28 yr). Significant correlations were indicated between the arm-curl scores and both isokinetic endurance (r = 0.452) and general endurance (r = 0.437); however, a very low nonsignificant correlation was found between the arm-curl and isokinetic maximal strength scores. Coaches must be aware of the fact that the repetitive arm-curl exercise contains a significant aerobic component and thus may contribute to aerobic fitness and arm muscle endurance but not necessarily to arm strength.

Analysis of foot and ankle kinematics after operative reduction of high-grade intra-articular fractures of the calcaneus.

BACKGROUND: High-grade calcaneal fractures represent a complex injury, with limited data to support the advisability of open reduction. Restoration of foot and ankle kinematics during walking, which has been previously shown to be significantly limited after nonoperative treatment, has never been studied after the operation. This study was designed to address this lack of information to assess the advisability of the operation in this respect. METHODS: Twenty patients with a minimum of 2 years after Open Reduction Internal Fixation (ORIF) for high-grade fractures were evaluated with a computerized gait analysis system, in addition to the radiographic assessment and functional questionnaires. Foot and ankle kinematic variables in the operated limbs were compared with contralateral limbs and with matched healthy control individuals. RESULTS: The kinematical gait analysis demonstrated recreation of normal ankle motions in operated patients. Subtalar motion demonstrated relative symmetry between operated and contralateral limbs, but it was still significantly limited compared with healthy controls. Bohler angle was between 15° and 35°. Functional questionnaires and rate of postoperative complications supported the generalizability of our operated group compared with previous literature assessing similar injuries. CONCLUSIONS: In high-grade calcaneal fractures, when recreation of gross calcaneal anatomy is obtained during the operation, walking ankle motion is recreated as well. However, subtalar motions, although recreated to a certain extent, still demonstrate limitations when compared with noninjured individuals. These results support the advisability of the operation in these complex injuries, but they demonstrate that subtalar motion is not completely normalized despite a favorable anatomic outcome.

Analysis of foot structure in athletes sustaining proximal fifth metatarsal stress fracture.

BACKGROUND: In the past, several studies provided anecdotal descriptions of high-arched feet in individuals sustaining proximal fifth metatarsal stress fractures. This relationship has never been supported by scientific evidence. Our objective was to examine whether athletes who sustained this injury had an exceptional static foot structure or dynamic loading pattern. MATERIALS AND METHODS: Ten injured professional soccer players who regained full professional activity following a unilateral proximal fifth metatarsal stress fracture and ten control soccer players were examined. Independent variables included static evaluation of foot and arch structure, followed by dynamic plantar foot pressure evaluation. Each variable was compared between injured, contra-lateral uninjured, and control feet. RESULTS: Static measurements of foot and arch structure did not reveal differences among the groups. However, plantar pressure evaluation revealed relative unloading of the fourth metatarsal in injured and uninjured limbs of injured athletes compared with control, while the fifth metatarsal revealed pressure reduction only in the injured limbs of injured athletes. CONCLUSION: Athletes who sustained proximal fifth metatarsal stress fracture were not characterized by an exceptional static foot structure. Dynamically, lateral metatarsal unloading during stance may either play a role in the pathogenesis of the injury, or alternately represent an adaptive process. CLINICAL RELEVANCE: Footwear fabrication for previously injured athletes should not categorically address cushioning properties designed for high-arch feet, but rather focus on individual dynamic evaluation of forefoot loading, with less attention applied to static foot and arch characteristics.

Is the interaction between HIF1A P582S and ACTN3 R577X determinant for power/sprint performance?

Hypoxia-inducible factor 1 (HIF-1) is a transcription factor that regulates gene expression in response to hypoxia and has been associated with athletic performance. The aims of this study were (1) to determine the frequency distribution of HIF1A Pro582Ser (rs11549465) polymorphism among 155 Israeli athletes (sprinters and endurance athletes) and 240 healthy controls and (2) to analyze the influence of the interaction between HIF1A Pro582Ser and ACTN3 R577X (rs1815739) genotypes on sprint performance. There were no differences across the HIF1A genotype and allele frequencies among endurance athletes, sprinters, and controls. Similarly, no differences were found between the subgroups of top-level and national-level endurance athletes, or between top-level and national-level sprinters. Conversely, interaction effects were found between HIF1A Pro582Ser and ACTN3 R577X polymorphisms and sprinters. The proportion of HIF1A Pro/Pro + ACTN3 R/R genotypes was significantly higher in sprinters than in endurance athletes and healthy controls (P = .002). In addition, the odds ratio for HIF1A Pro/Pro + ACTN3 R/R genotype carriers being a sprinter was 2.25 (95% confidence interval, 1.24-4.1); and that for HIF1A Pro/Pro + ACTN3 R/R genotype carriers being an endurance athlete was 0.5 (95% confidence interval, 0.2-1.24). We conclude that HIF1A Pro582Ser polymorphism by itself is not critical in determining sprint performance. However, sprinter performance is determined by the interaction between the wild-type HIF1A Pro/Pro genotype and ACTN3 RR genotype.

Subtalar kinematics following resection of tarsal coalition.

BACKGROUND: Pain relief and functional improvement in the short term have been demonstrated in the majority of patients with tarsal coalition following resection. Recreation of normal subtalar kinematics is an important goal in these patients as well, and may have long term implications. The purpose of our study was to examine whether kinematic variables of foot motion are normalized following resection of tarsal coalition. MATERIALS AND METHODS: This study compared three groups: nine candidates for resection of tarsal coalition, nine patients between 2 and 4 years after bar resection, and nine control subjects. Ankle hindfoot scoring was evaluated according to the AOFAS. Kinematic analysis of subtalar motion in the coronal plane and in the sagittal plane was performed using a computerized gait analysis system. RESULTS: Significantly increased passive subtalar range of motion and AOFAS ankle hindfoot scoring were demonstrated in postoperative subjects relative to preoperative subjects (p = 0.000). However, the kinematic analysis performed during walking, revealed similar, severe restriction of the subtalar eversion-inversion motion in postoperative and preoperative subjects. Angular velocity of the subtalar motion was also similar in both coalition groups, and was significantly increased compared with control. Kinematic analysis of foot motion in the sagittal plain demonstrated improved motion in postoperative subjects, which was comparable with the control group. CONCLUSION: Foot kinematics are not recreated following tarsal coalition resection, despite the favorable clinical outcome observed. CLINICAL RELEVANCE: Following resection of a tarsal coalition, patients continue to be subjected to increased loading and torque in their subtalar and adjacent articulations. This may promote further articular deterioration in the long term. Additional operative procedures or rehabilitation protocols should be examined to improve foot kinematics in this population.