The influence of the windlass mechanism on kinematic and kinetic foot joint coupling.

BACKGROUND: Previous research shows kinematic and kinetic coupling between the metatarsophalangeal (MTP) and midtarsal joints during gait. Studying the effects of MTP position as well as foot structure on this coupling may help determine to what extent foot coupling during dynamic and active movement is due to the windlass mechanism. This study's purpose was to investigate the kinematic and kinetic foot coupling during controlled passive, active, and dynamic movements. METHODS: After arch height and flexibility were measured, participants performed four conditions: Seated Passive MTP Extension, Seated Active MTP Extension, Standing Passive MTP Extension, and Standing Active MTP Extension. Next, participants performed three heel raise conditions that manipulated the starting position of the MTP joint: Neutral, Toe Extension, and Toe Flexion. A multisegment foot model was created in Visual 3D and used to calculate ankle, midtarsal, and MTP joint kinematics and kinetics. RESULTS: Kinematic coupling (ratio of midtarsal to MTP angular displacement) was approximately six times greater in Neutral heel raises compared to Seated Passive MTP Extension, suggesting that the windlass only plays a small kinematic role in dynamic tasks. As the starting position of the MTP joint became increasingly extended during heel raises, the amount of negative work at the MTP joint and positive work at the midtarsal joint increased proportionally, while distal-to-hindfoot work remained unchanged. Correlations suggest that there is not a strong relationship between static arch height/flexibility and kinematic foot coupling. CONCLUSIONS: Our results show that there is kinematic and kinetic coupling within the distal foot, but this coupling is attributed only in small measure to the windlass mechanism. Additional sources of coupling include foot muscles and elastic energy storage and return within ligaments and tendons. Furthermore, our results suggest that the plantar aponeurosis does not function as a rigid cable but likely has extensibility that affects the effectiveness of the windlass mechanism. Arch structure did not affect foot coupling, suggesting that static arch height or arch flexibility alone may not be adequate predictors of dynamic foot function.

Runners with mid-portion Achilles tendinopathy have greater triceps surae intracortical inhibition than healthy controls.

OBJECTIVES: This study aimed to investigate short-interval intracortical inhibition (SICI) and muscle function in the triceps surae of runners with mid-portion Achilles tendinopathy (AT). METHODS: Runners with (n = 11) and without (n = 13) AT were recruited. Plantar flexor isometric peak torque and rate of torque development (RTD) were measured using an isokinetic dynamometer. Triceps surae endurance was measured as single-leg heel raise (SLHR) to failure test. SICI was assessed using paired-pulse transcranial magnetic stimulation during a sustained contraction at 10% of plantar flexor isometric peak torque. RESULTS: Triceps surae SICI was 14.3% (95% CI: -2.1 to 26.4) higher in AT than in the control group (57.9%, 95% CI: 36.2 to 79.6; and 43.6% 95% CI: 16.2 to 71.1, p = 0.032) irrespective of the tested muscle. AT performed 16 (95% CI: 7.9 to 23.3, p < 0.001) fewer SLHR repetitions on the symptomatic side compared with controls, and 14 (95% CI: 5.8 to 22.0, p = 0.004), fewer SLHR repetitions on the non-symptomatic compared with controls. We found no between-groups differences in isometric peak torque (p = 0.971) or RTD (p = 0.815). PERSPECTIVE: Our data suggest greater intracortical inhibition for the triceps surae muscles for the AT group accompanied by reduced SLHR endurance, without deficits in isometric peak torque or RTD. The increased SICI observed in the AT group could be negatively influencing triceps surae endurance; thus, rehabilitation aiming to reduce intracortical inhibition should be considered to improve patient outcomes. Furthermore, SLHR is a useful clinical tool to assess plantar flexor function in AT patients.

Hip Flexion Angles During Supine Range of Motion and Bodyweight Squats.

During the lowering phase of a squat, it has been observed that a posterior pelvic tilt (PPT) may occur when squatting to full depth. Research suggests that defaulting to compensatory movement strategies, such as PPT, during the squat may correlate with risk of lower extremity and trunk pathology. The purpose of this study was to examine hip flexion (HF) angles at the point when PPT occurs among three conditions: standard squats, heel raise squats, and supine passive HF; analyzing the differences in depth between standard and heel raise squats; and calculating differences in knee angles and ankle excursion between standard and heel raise squats. 28 participants performed bodyweight squats and underwent supine passive HF while outfitted with 32 retroreflective motion capture markers. Hip, knee, and ankle joint angles were extracted at the point of PPT. A one-way repeated measures ANOVA was used to determine differences in hip joint angles between conditions, and a paired sample t-test was used to compare knee angles, ankle excursion, and squat depth between standard and heel raise squats. HF angles at PPT remained unchanged across all conditions. However, significantly greater knee flexion, ankle excursion, and squat depth were observed in the heel raise squats compared to the standard squats. Results suggest that PPT is a compensatory movement that occurs as the femur compresses into the acetabulum once hip flexion has been exhausted.

Electromyographic Assessment of the Lower Leg Muscles during Concentric and Eccentric Phases of Standing Heel Raise.

Only a small number of muscle activation patterns from lower limbs have been reported and simultaneous muscle activation from several lower limb muscles have not yet been investigated. The purpose of this study was to examine any gender differences in surface electromyography (EMG) activity from six recorded lower limb muscles of the dominant limb at baseline (i.e., with the foot placed flat on the floor and in the neutral position), and during concentric and eccentric phases when performing a heel raise task. In total, 10 females and 10 males performed a standing heel raise task comprising of three continuous phases: baseline, unloading (concentric muscle action), and loading (eccentric muscle action) phases. Muscle activation from six muscles (gastrocnemius medialis, gastrocnemius lateralis, soleus, tibialis anterior, peroneus longus, and peroneus brevis) were measured using the Myon 320 EMG System. Root mean squared values of each muscle were calculated for each phase. Descriptive and inferential statistics were incorporated into the study. Statistically significant p values were set at 0.05. The results showed no significant differences between baseline, concentric, and eccentric phases with respect to each of the muscles investigated. Except for the gastrocnemius medialis at baseline and concentric phases, no significant differences were observed between genders or contractions. The data suggests that gender does not significantly influence the eccentric phase during the standing heel raise task.

Full thickness open tear of the tendoachilles - Functional outcomes following a stable, single stage repair.

OBJECTIVE: Open injuries of the Tendoachilles present a challenge to the treating surgeon. Although, common in our setting, there is a paucity of literature regarding management of the same. The purpose of this retrospective study was to analyse the functional outcomes following debridement and primary repair of open tears of the Tendoachilles. MATERIALS AND METHODS: Patients with open tears of the tendoachilles, between January 2012 to January 2017. After obtaining demographic data, including mechanism of injury, all patients were managed by adequate debridement and primary repair, by Pennington's modification of Kessler's technique in a single sitting, paratenon closed circumferentially, plantaris reinforcement used when end to end repair couldn't be achieved. Below knee cast for 2 months. Weight bearing started at three months. Statistical analysis using paired t-test for calf circumference, ankle range of motion comparing with uninjured limb. Functional outcome assessment by AOFAS hindfoot score and Achilles tendon rupture score. RESULTS: 23 male patients, mean age 35, were analysed. Field injury was the most common mechanism, with slip in Indian lavatory pans accounting for four patients. Average time to surgery from injury was 22 hours. Plantaris reinforcement in one case. No case of wound dehiscence, scar adherence, tendon rerupture or infection. One patient had serous discharge at three weeks which settled with oral antibiotics. 21 patients performed single heel raise. There was no significant difference in calf circumference and ankle range of motion compared to uninjured limb. Mean AOFAS score was 92, mean Achilles tendon rupture score 77. CONCLUSION: Though open injuries of the tendoachilles is fraught with complications, early debridement, adequate repair of the tendon edges with circumferential closure of the paratenon, yields adequate functional outcomes with minimal complications.

Effects of a "toes-off" modified heel raise on muscle coordination in non-dancers, dancers, and dancers with flexor hallucis longus tendinopathy.

BACKGROUND: Tendinopathy of the flexor hallucis longus, commonly called "dancer's tendinitis", is a prevalent injury among female ballet dancers. Limited success of non-surgical interventions leads to many dancers undergoing tenolysis surgeries with risks and recovery times that can be detrimental to a dance career. The purpose of this study was to evaluate lower limb kinematics and muscle coordination during a modified traditional heel raise exercise where the toes hang off the edge of the support surface. We hypothesized this would decrease activation of the flexor hallucis longus and increase activation of larger plantarflexors. METHODS: Healthy non-dancers (n = 11), healthy dancers (n = 10), and dancers with flexor hallucis longus tendinopathy (n = 9) performed traditional ("toes-on") and modified ("toes-off") heel raises with kinematic and electromyographic instrumentation of the lower leg. FINDINGS: Participants maintained ankle excursion with the toes-off modification, while metatarsophalangeal joints had reduced excursion and greater excursion variability. Most healthy dancers (9/10) decreased flexor hallucis longus activation as predicted, but dancers with flexor hallucis longus tendinopathy showed a variable response with some decreasing activation (3/9) but others increasing activation up to 4-times. There were no changes in activation of other plantarflexors. Across groups, intrinsic foot muscle activation decreased with the toes-off modification. INTERPRETATION: The toes-off modification decreased flexor hallucis longus activation in most of the healthy dancers but was insufficient to shift muscle coordination from the flexor hallucis longus to larger plantarflexors in dancers with flexor hallucis longus tendinopathy. Future work should investigate clinical cues or modifications to this "toes-off" heel raise intervention.

A novel simplified biomechanical assessment of the heel pad during foot plantarflexion.

The heel pad (HP) which is located below the calcaneus comprises a composition of morphometrical and morphological arrangements of soft tissues that are influenced by factors such as gender, age and obesity. It is well known that HP pain and Achilles tendonitis consist of discomfort, pain and swelling symptoms that usually develop from excessive physical activities such as walking, jumping and running. The purpose of this study was to develop biomechanical techniques to evaluate the function and characteristics of the HP. Ten healthy participants (five males and five females) participated in this laboratory-based study, each performing a two-footed heel raise to mimic the toe-off phase during human locomotion. Twenty-six (3 mm) retroreflective markers were attached to the left and right heels (thirteen markers on each heel). Kinematic data was captured using three-dimensional motion analysis cameras synchronised with force plates. Descriptive and multivariate statistical tests were used in this study. In addition, a biomechanical technique that utilises only six markers from 26 markers to assess HP deformation and function has been developed and used in this study. Overall HP displacement was significantly higher in males on the most lateral part of the right heel (p < 0.05). No significant differences were evident when comparing the non-dominant and dominant heels during the baseline, unloading and loading phases (p > 0.05). Findings from this study suggested that biomechanical outputs expressed as derivatives from tracked HP marker movements can morphologically and morphometrically characterise HP soft tissue deformation changes. The outcome of this study highlights the importance of 3D motion analysis being used as a potential prospective intervention to quantify the function / characteristics of the heel pad soft tissues.

Sex differences in heel pad stiffness during in vivo loading and unloading.

Due to conflicting data from previous studies a new methodological approach to evaluate heel pad stiffness and soft tissue deformation has been developed. The purpose of this study was to compare heel pad (HP) stiffness in both limbs between males and females during a dynamic unloading and loading activity. Ten males and 10 females volunteered to perform three dynamic trials to unload and load the HP. The dynamic protocol consisted of three continuous phases: foot flat (baseline phase), bilateral heel raise (unloading phase) and foot flat (loading phase) with each phase lasting two seconds. Six retroreflective markers (3 mm) were attached to the skin of the left and right heels using a customised marker set. Three-dimensional motion analysis cameras synchronised with force plates collected the kinematic and kinetic data throughout the trials. Three-way repeated measures ANOVA together with a Bonferroni post hoc test were applied to the stiffness and marker displacement datasets. On average, HP stiffness was higher in males than females during the loading and unloading phases. ANOVA results revealed no significant differences for the stiffness and displacement outputs with respect to sex, sidedness or phase interactions (p > .05) in the X, Y and Z directions. Irrespective of direction, there were significant differences in stiffness between the baseline and unloading conditions (p < .001) but no significant differences between the baseline and loaded conditions (p = 1.000). Post hoc analyses for the marker displacement showed significant differences between phases for the X and Z directions (p < .032) but no significant differences in the Y direction (p > .116). Finally, females portrayed lower levels of mean HP stiffness whereas males had stiffer heels particularly in the vertical direction (Z) when the HP was both unloaded and loaded. High HP stiffness values and very small marker displacements could be valuable indicators for the risk of pathological foot conditions.

Biomechanical differences in double poling between sexes and level of performance during a classical cross-country skiing competition.

Biomechanical differences in double poling (DP) between sex and performance level were investigated in female and male cross-country skiers during a classical race (10/15 km). Skiers were divided into faster and slower on basis of race performance: females faster (n=20), females slower (n=20), males faster (n=20), and males slower (n=20). Based on video analysis while DP in a flat section of the track, joint and pole angles at pole plant (PP) and pole-off, cycle characteristics and the use and coordination pattern of heel-raise (raise of heels from the ground to have a higher body position at PP) were analysed. Faster females and males had 4.3% and 7.8% higher DP velocity than their slower counterparts (both P<0.001). Faster males had 6.5% longer cycles than slower males (P<0.001). Faster skiers stopped heel-raise later than slower skiers (females: 2.0±3.4% vs. -1.0±3.5%, P<0.05; males: 3.9±2.4% vs. 0.8±3.2% of cycle time in relation to PP, P<0.001). At PP, faster skiers and male skiers had a smaller pole angle and greater ankle to hip and ankle to shoulder angle with respect to vertical, resulting in a more distinct forward body lean. However, the majority of the differences are likely due to higher DP velocity.

Early weight-bearing in nonoperative treatment of acute Achilles tendon rupture did not influence mid-term outcome: a blinded, randomised controlled trial.

PURPOSE: Acute Achilles tendon rupture leads to impaired outcome at short term, but little is known concerning medium-term results. The aim of the present study was to investigate the influence of early weight-bearing on clinical outcome 4.5 years after nonoperative treatment of acute Achilles tendon rupture. METHOD: The study was performed as a medium-term follow-up on patients included in a randomised controlled trial. Both groups were treated with nonoperative management and controlled early motion. The intervention group was allowed full weight-bearing from day 1, and the control group was non-weight-bearing for 6 weeks. 60 patients were randomised 1:1. Of those, 56 were eligible for inclusion in the medium-term follow-up and 37 participated (18 control, 19 intervention). The outcomes were Achilles tendon Total Rupture Score (ATRS) and heel raise work performed at an average of 4.5 years after the initial injury. Statistical analysis was performed using paired t tests and linear regression. RESULTS: No differences were found between control and intervention groups at 4.5 years. ATRS scores consistently improved in both the intervention and the control groups from 0.5 to 1 year and from 1 to 4.5 years, ending up at 80.5 on average after 4.5 years. Heel raise height kept improving from 0.5 to 4.5 years, reaching a limb symmetry index of 82.4%. The heel raise work improvement from 0.5 to 1 year did not continue. No significant change was found from 1 to 4.5 years, ending at a limb symmetry index of 60%. CONCLUSION: Early weight-bearing did not influence outcome 4.5 years after nonoperative treatment of acute Achilles tendon rupture. The calf muscle of the injured limb performs 40% less work, when compared to the healthy limb, though lifting height recovers better. LEVEL OF EVIDENCE: II. CLINICAL TRIALS IDENTIFIER: NCT02760784.

Functional leg length discrepancy between theories and reliable instrumental assessment: a study about newly invented NPoS system.

BACKGROUND: In spite the instinct social&financial impact of Leg Length Discrepancy (LLD), controversial and conflicting results still exist regarding a reliable assessment/correction method. For proper management it's essential to discriminate between anatomical&functional Leg Length Discrepancy (FLLD). With the newly invented NPoS (New Postural Solution), under the umbrella of the collaboration of PRM Department, Tor Vergata University with Baro Postural Instruments srl, positive results were observed in both measuring& compensating the hemi-pelvic antero-medial rotation in FLLD through personalized bilateral heel raise using two NPoS components: Foot Image System (FIS) and Postural Optimizer System (POS). This led our research interest to test the validity of NPoS as a preliminary step before evaluating its implementations in postural disorders. METHODS: After clinical evaluation, 4 subjects with FLLD have been assessed by NPoS. Over a period of 2 months, every subject was evaluated 12 times by two different operators, 48 measurements in total, results have been verified in correlation to BTS GaitLab results. RESULTS: Intra-Operator&inter-operator variability analysis showed statistically insignificant differences, while inter-method variability between NPoS and BTS parameters expressed a linear correlation. CONCLUSION: Results suggest a significant validity of NPoS in assessment&correction of FLLD, with high degree of reproducibility with minimal operator dependency. This can be considered a base for promising clinical implications of NPoS as a reliable cost effective postural assessment/corrective tool. LEVEL OF EVIDENCE: V.

Effects of different heel-raise-lower exercise interventions on the strength of plantarflexion, balance, and gait parameters in stroke survivors.

The objective of this study was to investigate the effects of Heel-Raise-Lower Exercise (HRLE) interventions on the strength of plantarflexion, balance, and gait parameters in people with stroke. Specifically, this study compared the two different HRLEs to identify whether heels raise-lower with forefoot on a block (HRB) is more effective or ineffective to enhance strength and functional capacities than heels raise-lower on a level floor (HRL) exercise in people with stroke. Repetitive heel raise-lower is a common exercise for improving the strength and power of ankle plantarflexors. It is a simple movement, requires no equipment, and can be performed at home. Each group of 10 people with stroke was given either HRB training or HRL training. The subjects performed the exercise 100 times per day, 5 days per week for 6 weeks. The strength of plantarflexors, static/dynamic balance, and gait parameters were measured using the manual muscle test (MMT), a Biodex Balance System (BBS) SD, and the GAITRite system. After 6 weeks of treatment, there were significant increases in the plantarflexors strength in both groups: by 34% in the HRB group and by 21% in the HRL group. Static and dynamic balance and gait speed also increased significantly in both groups. However, cadence, the paretic side single limb support period (SLSP), paretic side step length, and paretic side stride length significantly increased only in the HRB group. The HRB improved significantly the plantar flexor strength of the paretic side, gait speed, and cadence compared to the HRL.

Calf-raise senior: a new test for assessment of plantar flexor muscle strength in older adults: protocol, validity, and reliability.

PURPOSE: This study aimed to develop a new field test protocol with a standardized measurement of strength and power in plantar flexor muscles targeted to functionally independent older adults, the calf-raise senior (CRS) test, and also evaluate its reliability and validity. PATIENTS AND METHODS: Forty-one subjects aged 65 years and older of both sexes participated in five different cross-sectional studies: 1) pilot (n=12); 2) inter- and intrarater agreement (n=12); 3) construct (n=41); 4) criterion validity (n=33); and 5) test-retest reliability (n=41). Different motion parameters were compared in order to define a specifically designed protocol for seniors. Two raters evaluated each participant twice, and the results of the same individual were compared between raters and participants to assess the interrater and intrarater agreement. The validity and reliability studies involved three testing sessions that lasted 2 weeks, including a battery of functional fitness tests, CRS test in two occasions, accelerometry, and strength assessments in an isokinetic dynamometer. RESULTS: The CRS test presented an excellent test-retest reliability (intraclass correlation coefficient [ICC] =0.90, standard error of measurement =2.0) and interrater reliability (ICC =0.93-0.96), as well as a good intrarater agreement (ICC =0.79-0.84). Participants with better results in the CRS test were younger and presented higher levels of physical activity and functional fitness. A significant association between test results and all strength parameters (isometric, r=0.87, r2=0.75; isokinetic, r=0.86, r2=0.74; and rate of force development, r=0.77, r2=0.59) was shown. CONCLUSION: This study was successful in demonstrating that the CRS test can meet the scientific criteria of validity and reliability. The test can be a good indicator of ankle strength in older adults and proved to discriminate significantly between individuals with improved functionality and levels of physical activity.

Three-dimensional evaluation of heel raise test in pediatric planovalgus feet and normal feet.

Planovalgus foot is a common pediatric deformity which may be associated with pain. To evaluate flexibility of the foot, the heel raise test is used. During this test the arch and hindfoot are assessed. Several studies have described planovalgus foot based on 3D gait and standing analysis. However, no studies have evaluated foot flexibility during heel raise using an objective 3D analysis. Therefore, the purpose of this study is to evaluate the flexibility of planovalgus feet during the heel raise test using an objective 3D assessment and to determine whether any hypotheses can be generated about potential differences between painful and painless flexible planovalgus feet and reference feet. Here, 3D foot analysis was conducted in 33 children (7 reference feet, 16 painless, and 10 painful flexible planovalgus feet) during the heel raise test. To identify the characteristics of planovalgus foot, the concept of 3D projection angles was used as introduced in the Heidelberg Foot Measurement Method (HFMM), with a modified marker set. All feet showed dynamic movements of the medial arch and hindfoot from valgus to varus position during heel raise. Reference feet had the smallest range of motion, perhaps due to joint stability and absence of foot deformity. Painful and painless flexible planovalgus feet demonstrated similar movements. No significant differences were found between the painful and painless groups. However, the kinematics of the pain group seemed to differ more from those of the reference group than did kinematics of the painless group. This assessment is a new, practical, and objective method to measure the flexibility of small children's feet.

Comparison of ankle plantar flexor activity between double-leg heel raise and walking.

[Purpose] We aimed to evaluate the difference in the muscle activity between the double-leg heel raise (DHR) and treadmill walking. [Subjects] Thirty healthy males aged 21.5 ± 1.6 years (body mass 63.6 ± 9.3 kg, height 171.0 ± 4.5 cm) participated in the study. [Methods] Electromyograms were simultaneously recorded from both heads of the gastrocnemius and the soleus of the right side during the DHR and treadmill walking. The DHR conditions were maximum plantar flexion (MPF), 3/4 MPF, 2/4 MPF, and 1/4 MPF, and the walking speeds were 20, 40, 60, 80, and 100 m/min. [Results] The muscle activity during the DHR and walking significantly increased with increments in the height of the heel raise and walking speed, respectively. Comparison of the muscle activity at MPF with that at each walking speed revealed that the muscle activity in the soleus and gastrocnemius medial head during walking exceeded that during the DHR in less than 3.3% of cases. [Conclusion] The DHR test is useful for evaluating the ankle plantar flexor activity necessary for walking.

Effect of tirasemtiv, a selective activator of the fast skeletal muscle troponin complex, in patients with peripheral artery disease.

Tirasemtiv (CK-2017357), a novel small-molecule activator of the fast skeletal muscle troponin complex, slows the rate of calcium release from troponin, thus sensitizing fast skeletal muscle fibers to calcium. In preclinical studies, tirasemtiv increased muscle force and delayed the onset and reduced the extent of muscle fatigue during hypoxia in vitro and muscle ischemia in situ. This study evaluated the effect of single doses of tirasemtiv on measures of skeletal muscle function and fatigability in patients with stable calf claudication due to peripheral artery disease (PAD). Sixty-one patients with an ankle-brachial index ≤0.90 in the leg with claudication received single double-blind doses of tirasemtiv 375 mg and 750 mg and matching placebo in random order about 1 week apart. After 33 patients were treated, the 750 mg dose was decreased to 500 mg due to adverse events and these dose groups were combined for analysis. On each study day, bilateral heel-raise testing was performed before and at 3 and 6 hours after dosing; a 6-minute walk test was performed at 4 hours after dosing. Claudicating calf muscle performance was increased at the highest dose and plasma concentration of tirasemtiv; however, the 6-minute walk distance decreased with both the dose and plasma concentration of tirasemtiv, possibly due to dose-related adverse events, particularly dizziness, that could impede walking ability. In conclusion, the mechanism of fast skeletal muscle troponin activation improved muscle function but not 6-minute walking distance in patients with claudication due to PAD. CLINICALTRIALSGOV IDENTIFIER NCT01131013:

Validity of the single limb heel raise test to predict lower extremity disablement in patients with sporadic inclusion body myositis.

PURPOSE: To determine the validity of the single limb heel raise (SLHR) test as a potential screening tool to detect lower extremity disability in patients with sporadic inclusion body myositis (sIBM). METHODS: We compared gait speed and fall history between subjects with sIBM who either could complete one SLHR (SLHR group) or could not complete one SLHR. Discriminative validity was established by comparing between group differences in functional measures based on group assignment. Receiver operating characteristics curve analysis was used to determine the predictive validity of completing one repetition on the SLHR test. Spearman correlations were used to determine the association between gait kinematics and number of repetitions achieved on the SLHR test. RESULTS: Forty-three subjects (13 females) were studied. The SLHR group (n = 21) showed significantly greater gait speed (p < 0.001) and decreased gait aid use (p < 0.05) compared to the no SLHR group (n = 22). SLHR cut scores of 1, 20, and 22 repetitions maximized positive likelihood ratios (+LR) for the ability to walk at 54.9 (+LR. 2.2), 63.2 (+LR. 9.5), and 73.1 m/min (+LR. 5.0), respectively. CONCLUSION: The SLHR test demonstrates adequate discriminative and predictive validity as a screening tool for lower extremity disablement in patients with sIBM. Implications for Rehabilitation The SLHR test has adequate reliability and validity to screen for the presence of lower extremity disablement in patients with sIBM. Results of this rapid field test may be used to guide the need for rehabilitation services to mitigate the effects of slow gait speeds in patients with sIBM.

Localised muscle tissue oxygenation during dynamic exercise with whole body vibration.

Despite increasing use of whole body vibration during exercise an understanding of the exact role of vibration and the supporting physiological mechanisms is still limited. An important aspect of exercise analysis is the utilisation of oxygen, however, there have been limited studies considering tissue oxygenation parameters, particularly during dynamic whole body vibration (WBV) exercise. The aim of this study was to determine the effect of adding WBV during heel raise exercises and assessing changes in tissue oxygenation parameters of the lateral gastrocnemius using Near Infra Red Spectroscopy (NIRS). Twenty healthy subjects completed ten alternating sets of 15 heel raises (vibration vs. no vibration). Synchronous oxygenation and motion data were captured prior to exercise to determine baseline levels, for the duration of the exercise and 20 sec post exercise for the recovery period. Both vibration and no vibration conditions elicited a characteristic increase in deoxyhaemoglobin and decreases in oxyhaemoglobin, total haemoglobin, tissue oxygenation index and normalised tissue haemoglobin index which are indicative of local tissue hypoxia. However, the addition of vibration elicited significantly lower (p < 0. 001) depletions in oxyhaemoglobin, total haemoglobin, normalised tissue haemoglobin index but no significant differences in deoxyhaemoglobin. These findings suggest that addition of vibration to exercise does not increase the cost of the exercise for the lateral gastrocnemius muscle, but does decrease the reduction in local muscle oxygenation parameters, potentially resulting from increased blood flow to the calf or a vasospastic response in the feet. However, further studies are needed to establish the mechanisms underlying these findings. Key pointsWhole body vibration affects tissue oxygenation of the lateral gastrocnemius.The underlying mechanism could be either increased blood flow or a vasospastic response in the feet.The local metabolic cost of heel raise activity on the lateral gastrocnemius does not appear to be increased by whole body vibration.

THE EFFECTS OF EXERCISE OF THE PERONEUS LONGUS AND TIBIALIS POSTERIOR MUSCLES ON HEEL RAISE / 体力科学

Objective: This study aimed to clarify changes in planter pressure at the 1, 2, 5 metatarsal head, and muscle activities resulting from exercise of the peroneus longus (PL) or tibialis posterior (TP) muscles. Method: Nine subjects (3 male, 6 female) were recruited. Before and after exercise, planter pressure at the metatarsal heads and the activities of PL, TP, tibialis anterior, and soleus muscles were recorded during heel raising using electromyography and a foot sensor. The first exercise was a maximal isometric contraction of the PL and peroneus brevis (PB). The second was contraction of the TP, and the third was of all three, the PL, PB, and TP. Result: The amount of planter pressure at the first metatarsal head increased after PL exercise. The standard deviation at the second metatarsal head decreased after PL and TP exercise, but showed no change after PL exercise. Conclusion: After PL and TP exercise, heel raises were possible with few perturbations at the metatarsal head. After PL exercise, the amount of planter pressure at the first metatarsal head increased, but there was no change in perturbations. The results show that it is necessary to consider the effect of short time exercise.