Examining the Degree of Pain Reduction Using a Multielement Exercise Model with a Conventional Training Shoe Versus an Ultraflexible Training Shoe for Treating Plantar Fasciitis

Abstract

Plantar fasciitis is a common injury to the plantar aponeurosis, manifesting as pain surrounding its proximal insertion at the medial calcaneal tubercle. Pain is typically worse in the morning when getting out of bed, and may subside after the tissue is sufficiently warmed up. For running-based athletes and individuals who spend prolonged periods of time on their feet at work, plantar fasciitis may become recalcitrant to conservative treatments such as ice, rest, and anti-inflammatory medication. Exercise-based therapies have received only limited attention in the literature for this common problem, yet they are becoming increasingly validated for pain relief and positive tissue remodeling at other sites of similar soft-tissue overuse injury. This study reports on pain outcomes in individuals experiencing chronic plantar fasciitis whiles wearing a shoe with an ultraflexible midsole (Nike Free 5.0) (FREE) versus a conventional training (CON) shoe in a 12-week multielement exercise regimen, and after a 6-month follow-up. Adults with ≥ 6-month history of painful heel pain were recruited and randomly assigned to wear 1 of the 2 shoes. All subjects completed the same exercise protocol. A visual analogue scale item tracked peak pain in the preceding 24 hours taken at baseline, 6- and 12-week points, and at the 6-month follow-up. Twenty-one subjects completed the program (9 FREE; 12 CON). Both groups reported significant improvements in pain by the 6-month follow-up, and the FREE group reported an overall reduced level of pain throughout the study as a result of lower mean pain scores at the midpoint and post-test compared with the CON group. The exercise regimen employed in this study appears to reduce pain associated with chronic plantar fasciitis, and in doing so, the Nike 5.0 shoe may result in reductions in pain earlier than conventional running shoes.     

Does pre‐exercise static stretching inhibit maximal muscular performance? A meta‐analytical review

We applied a meta‐analytical approach to derive a robust estimate of the acute effects of pre‐exercise static stretching (SS) on strength, power, and explosive muscular performance. A computerized search of articles published between 1966 and December 2010 was performed using PubMed, SCOPUS, and Web of Science databases. A total of 104 studies yielding 61 data points for strength, 12 data points for power, and 57 data points for explosive performance met our inclusion criteria. The pooled estimate of the acute effects of SS on strength, power, and explosive performance, expressed in standardized units as well as in percentages, were ?0.10 [95% confidence interval (CI): ?0.15 to ?0.04], ?0.04 (95% CI: ?0.16 to 0.08), and ?0.03 (95% CI: ?0.07 to 0.01), or ?5.4% (95% CI: ?6.6% to ?4.2%), ?1.9% (95% CI: ?4.0% to 0.2%), and ?2.0% (95% CI: ?2.8% to ?1.3%). These effects were not related to subject's age, gender, or fitness level; however, they were more pronounced in isometric vs dynamic tests, and were related to the total duration of stretch, with the smallest negative acute effects being observed with stretch duration of ≤45 s. We conclude that the usage of SS as the sole activity during warm‐up routine should generally be avoided.     

Applicability of contrast‐enhanced ultrasound in the diagnosis of plantar fasciitis

Contrast‐enhanced ultrasound (CEUS) is used to visualize the microvascularization in various tissues. The purpose of this study was to investigate whether CEUS could be used to visualize the microvascular volume (MV) in the plantar fascia, and to compare the method to clinical symptoms and B‐mode ultrasound (US) in patients with plantar fasciitis (PF). Twenty patients with unilateral PF were included and were divided by US in insertional thickening (10), midsubstance thickening (5), and no US changes (5). The MV was measured simultaneously in both heels. Four areas in the plantar fascia and plantar fat pad were measured independently by two observers. Inter‐ and intra‐observer correlation analyses were performed. The asymptomatic heels showed a constantly low MV, and for the whole group of patients, a significantly higher MV was found in the symptomatic plantar fascia and plantar fat pad. Inter‐observer correlation as well as intra‐observer agreement was excellent. The MV in the plantar fascia and plantar fat pad can be measured reliably using CEUS, suggesting that it is a reproducible method to examine patients with plantar fasciitis.     

Running injuries in novice runners enrolled in different training interventions: a pilot randomized controlled trial

The purpose of this trial was to evaluate injury risk in novice runners participating in different strength training interventions. This was a pilot randomized controlled trial. Novice runners (n = 129, 18–60 years old, <2 years recent running experience) were block randomized to one of three groups: a “resistance” strength training group, a “functional” strength training group, or a stretching “control” group. The primary outcome was running related injury. The number of participants with complaints and the injury rate (IR = no. injuries/1000 running hours) were quantified for each intervention group. For the first 8 weeks, participants were instructed to complete their training intervention three to five times a week. The remaining 4 months was a maintenance period. Trial registration: NCT01900262. A total of 52 of the 129 (40%) novice runners experienced at least one running related injury: 21 in the functional strength training program, 16 in the resistance strength training program and 15 in the control stretching program. Injury rates did not differ between study groups [IR = 32.9 (95% CI 20.8, 49.3) in the functional group, IR = 31.6 (95% CI 18.4, 50.5) in the resistance group, and IR = 26.7 (95% CI 15.2, 43.2)] in the control group. Although this was a pilot assessment, home‐based strength training did not appear to alter injury rates compared to stretching. Future studies should consider methods to minimize participant drop out to allow for the assessment of injury risk. Injury risk in novice runners based on this pilot study will inform the development of future larger studies investigating the impact of injury prevention interventions.     

Translation and validation of the Danish Foot Function Index (FFI‐DK)

The objective of this study was to translate the Foot Function Index (FFI) for use in Danish‐speaking patients with foot complaints. The FFI consists of 23 items scored on a numeric rating scale from 0 to 10. The 23 items are grouped into three subscales: pain (nine items), activity limitation (five items), and disability (nine items). The Danish FFI was developed according to the recommended forward/backward translation protocol. The data analysis included reliability [intraclass correlation coefficient (ICC) 2.1] and internal consistency (Cronbach's alpha). Excellent internal consistency was shown for the three subscales: pain (0.99), disability (0.98), and activity limitation (0.98), as for the total score (0.97). The test‐retest reliability was excellent: pain subscale: ICC 0.98 [95% confidence interval (CI): 0.97–0.99]; activity limitation subscale: ICC: 0.95 (95% CI: 0.91–0.98); disability subscale: ICC 0.97 (95% CI: 0.95–0.98); total score: ICC: 0.95 (95% CI: 0.91 to 0.98). The mean difference between test and retest was below 1 point and P > 0.08. Bland–Altman plots showed no significant or clinically relevant differences from test to retest in any of the subscales or in the total score. The Danish version of the FFI was found to be valid and reliable and therefore acceptable for use in the Danish population.     

Plantar fasciitis and calcaneal spur formation are associated with abductor digiti minimi atrophy on MRI of the foot

Objective To determine the association of atrophy of the abductor digiti minimi muscle (ADMA), an MRI manifestation of chronic compression of the inferior calcaneal nerve suggesting the clinical diagnosis of Baxter’s neuropathy, with MRI markers of potential etiologies, including calcaneal spur formation, plantar fasciitis, calcaneal edema, Achilles tendinosis and posterior tibial tendon dysfunction (PTTD). Materials and methods Prevalence of calcaneal spur formation, plantar fasciitis, calcaneal edema, Achilles tendinosis and PTTD was assessed retrospectively on 100 MRI studies with ADMA and 100 MRI studies without ADMA. Patients ranged in age from 10–92 years. Pearson chi-square analyses and Fisher’s exact test were used to compare prevalence of the above findings in patients with and without ADMA. Logistic regression was used to determine which variables were significantly associated with ADMA. Results Among patients with ADMA, there was significantly greater age (57.2 years vs 40.8 years, p < 0.001), presence of Achilles tendinosis (22.0% vs 3.0%, P < 0.001), calcaneal edema (15.0% vs 3.0%, P = 0.005), calcaneal spur (48.0% vs 7.0%, P < 0.001), plantar fasciitis (52.5% vs 11.0%, P < 0.001), and PTTD (32.0% vs 11.0%, P < 0.001). After multivariate logistic regression analysis, only age [odds ratio (OR) 1.06, 95% confidence interval (CI) 1.03, 1.09], calcaneal spur (OR 3.60, 95% CI 1.28, 10.17), and plantar fasciitis (OR 3.35, 95% CI 1.31, 8.56) remained significant. Conclusion Advancing age, calcaneal spur, and plantar fasciitis are significantly associated with ADMA. Their high odds ratios support the notion of a possible etiologic role for calcaneal spur and plantar fasciitis in the progression to Baxter’s neuropathy.     

Effects of contract‐relax vs static stretching on stretch‐induced strength loss and length–tension relationship

The purpose of this study was to determine the acute effects of contract‐relax stretching (CRS) vs static stretching (SS) on strength loss and the length‐tension relationship. We hypothesized that there would be a greater muscle length‐specific effect of CRS vs SS. Isometric hamstring strength was measured in 20 healthy people at four knee joint angles (90°, 70°, 50°, 30°) before and after stretching. One leg received SS, the contralateral received CRS. Both stretching techniques resulted in significant strength loss, which was most apparent at short muscle lengths [SS: P = 0.025; stretching × angle P < 0.001; 11.7% at 90° P < 0.01; 5.6% at 70° nonsignificant (ns); 1.3% at 50° ns; ?3.7% at 30° ns. CRS: P < 0.001; stretching × angle P < 0.001; 17.7% at 90°, 13.4% at 70°, 11.4% at 50°, all P < 0.01, 4.3% at 30° ns]. The overall stretch‐induced strength loss was greater (P = 0.015) after CRS (11.7%) vs SS (3.7%). The muscle length effect on strength loss was not different between CRS and SS (stretching × angle × stretching technique P = 0.43). Contrary to the hypothesis, CRS did not result in a greater shift in the length–tension relationship, and in fact, resulted in greater overall strength loss compared with SS. These results support the use of SS for stretching the hamstrings.     

Effectiveness of orthotic shoe inserts in the long-distance runner

Five hundred questionnaires were distributed to long-distance runners who had used, or who were using orthotic shoe inserts for symptomatic relief of lower extremity complaints. Three hundred forty-seven (69.4%) responded (males, 71%; females, 29%). The mean age of the respondents was 36 years (range, 15 to 61). The average distance run per week was 39.6 miles (range, 5 to 98). The mean duration for use of the orthotic inserts was 23 months (range, 1 to 96). The predominant (63%) type of orthotic device used was flexible. The presumed diagnoses in the population studied were excessive pronation (31.1%), leg length discrepancy (13.5%), patellofemoral disorders (12.6%), plantar fasciitis (20.7%), Achilles tendinitis (18.5%), shin splints (7.2%), and miscellaneous (4.9%). Of the runners responding, 262 (75.5%) reported complete resolution or great improvement of their symptoms. Results of treatment with orthotic shoe inserts were independent of the diagnosis or the runner's level of participation. A high degree of overall satisfaction was demonstrated by the finding that 90% of the runners continued to use the orthotic devices even after resolution of their symptoms. Orthotic shoe inserts were most effective in the treatment of symptoms arising from biomechanical abnormalities, such as excessive pronation or leg length discrepancy. Along with other conservative measures, orthotic shoe inserts may allow the athlete to continue participation in running and avoid other treatment modalities that are more costly and time consuming, and therefore less acceptable to them.     

Influence of shoe midsole hardness on plantar pressure distribution in four basketball-related movements

This study examined how shoe midsole hardness influenced plantar pressure in basketball-related movements. Twenty male university basketball players wore customized shoes with hard and soft midsoles (60 and 50 Shore C) to perform four movements: running, maximal forward sprinting, maximal 45° cutting and lay-up. Plantar loading was recorded using an in-shoe pressure measuring system, with peak pressure (PP) and pressure time integral (PTI) extracted from 10 plantar regions. Compared with hard shoes, subjects exhibited lower PP in one or more plantar regions when wearing the soft shoes across all tested movements (Ps < 0.05). Lower PTI was also observed in the hallux for 45° cutting, and the toes and forefoot regions during the first step of lay-up in the soft shoe condition (Ps < 0.05). In conclusion, using a softer midsole in the forefoot region may be a plausible remedy to reduce the high plantar loading experienced by basketball players.     

A randomized trial of preexercise stretching for prevention of lower-limb injury

PURPOSE: This study investigated the effect of muscle stretching during warm-up on the risk of exercise-related injury. METHODS: 1538 male army recruits were randomly allocated to stretch or control groups. During the ensuing 12 wk of training, both groups performed active warm-up exercises before physical training sessions. In addition, the stretch group performed one 20-s static stretch under supervision for each of six major leg muscle groups during every warm-up. The control group did not stretch. RESULTS: 333 lower-limb injuries were recorded during the training period, including 214 soft-tissue injuries. There were 158 injuries in the stretch group and 175 in the control group. There was no significant effect of preexercise stretching on all-injuries risk (hazard ratio [HR] = 0.95, 95% CI 0.77-1.18), soft-tissue injury risk (HR = 0.83, 95% CI 0.63-1.09), or bone injury risk (HR = 1.22, 95% CI 0.86-1.76). Fitness (20-m progressive shuttle run test score), age, and enlistment date all significantly predicted injury risk (P < 0.01 for each), but height, weight, and body mass index did not. CONCLUSION: A typical muscle stretching protocol performed during preexercise warm-ups does not produce clinically meaningful reductions in risk of exercise-related injury in army recruits. Fitness may be an important, modifiable risk factor.     

Effect of training cessation on muscular performance: A meta‐analysis

The purpose of this study was to assess the effect of resistance training cessation on strength performance through a meta‐analysis. Seven databases were searched from which 103 of 284 potential studies met inclusion criteria. Training status, sex, age, and the duration of training cessation were used as moderators. Standardized mean difference (SMD) in muscular performance was calculated and weighted by the inverse of variance to calculate an overall effect and its 95% confidence interval (CI). Results indicated a detrimental effect of resistance training cessation on all components of muscular performance: [submaximal strength; SMD (95% CI) = ?0.62 (?0.80 to ?0.45), P < 0.01], [maximal force; SMD (95% CI) = ?0.46 (?0.54 to ?0.37), P < 0.01], [maximal power; SMD (95% CI) = ?0.20 (?0.28 to ?0.13), P < 0.01]. A dose–response relationship between the amplitude of SMD and the duration of training cessation was identified. The effect of resistance training cessation was found to be larger in older people (> 65 years old). The effect was also larger in inactive people for maximal force and maximal power when compared with recreational athletes. Resistance training cessation decreases all components of muscular strength. The magnitude of the effect differs according to training status, age or the duration of training cessation.     

The time course of the effects of constant‐angle and constant‐torque stretching on the muscle–tendon unit

The purpose of the present study was to examine the time course of passive range of motion (PROM), passive torque (PAS_TQ), and musculo‐tendinous stiffness (MTS) responses during constant‐angle (CA) and constant‐torque (CT) stretching of the leg flexors. Eleven healthy men [mean ± standard deviation (SD): age = 21.5 ± 2.3 years] performed 16 30‐s bouts of CA and CT stretching of the leg flexors. PROM, PAS_TQ, and MTS were measured during stretches 1, 2, 4, 8, and 16. For PROM and PAS_TQ, there were no differences between CA and CT stretching treatments (P > 0.05); however, there were stretch‐related differences (P < 0.001). PROM increased following one 30‐s bout of stretching (collapsed across CA and CT stretching) with additional increases up to 8 min of stretching. PAS_TQ decreased following one 30‐s bout of stretching (collapsed across CA and CT stretching) and continued to decrease up to 4 min of stretching. In contrast, only the CT stretching treatment resulted in changes to MTS (P < 0.001). MTS decreased after one 30‐s bout of CT stretching, with subsequent decreases in MTS up to 6 min of stretching. These results suggested that CT stretching may be more appropriate than a stretch held at a constant muscle length for decreasing MTS.     

Increasing preferred step rate during running reduces plantar pressures

Increasing preferred step rate during running is a commonly used strategy in the management of running‐related injuries. This study investigated the effect of different step rates on plantar pressures during running. Thirty‐two healthy runners ran at a comfortable speed on a treadmill at five step rates (preferred, ±5%, and ±10%). For each step rate, plantar pressure data were collected using the pedar‐X in‐shoe system. Compared to running with a preferred step rate, a 10% increase in step rate significantly reduced peak pressure (144.5±46.5 vs 129.3±51 kP a; P =.033) and maximum force (382.3±157.6 vs 334.0±159.8 N; P =.021) at the rearfoot, and reduced maximum force (426.4±130.4 vs 400.0±116.6 N; P =.001) at the midfoot. In contrast, a 10% decrease in step rate significantly increased peak pressure (144.5±46.5 vs 161.5±49.3 kP a; P =.011) and maximum force (382.3±157.6 vs 425.4±155.3 N; P =.032) at the rearfoot. Changing step rate by 5% provided no effect on plantar pressures, and no differences in plantar pressures were observed at the medial forefoot, lateral forefoot or hallux between the step rates. This study's findings indicate that increasing preferred step rate by 10% during running will reduce plantar pressures at the rearfoot and midfoot, while decreasing step rate by 10% will increase plantar pressures at the rearfoot. However, changing preferred step rate by 5% will provide no effect on plantar pressures, and forefoot pressures are unaffected by changes in step rate.     

In hip osteoarthritis,Nordic Walking is superior to strength training and home‐based exercise for improving function

This observer‐blinded, randomized controlled trial compared the short‐ and long‐term effects of 4 months of supervised strength training (ST) in a local fitness center, supervised Nordic Walking (NW) in a local park, and unsupervised home‐based exercise (HBE, control) on functional performance in 60+‐year‐old persons (n = 152) with hip osteoarthritis (OA) not awaiting hip replacement. Functional performance [i.e., 30‐s chair stand test (primary outcome), timed stair climbing, and 6‐min walk test] and self‐reported outcomes (i.e., physical function, pain, physical activity level, self‐efficacy, and health‐related quality of life) were measured at baseline and at 2, 4, and 12 months. Based on intention‐to‐treat‐analyses improvements [mean (95% CI)] after intervention in number of chair stands were equal in all three groups at 4 months [ST: 0.9 (0.2–1.6), NW: 1.9 (0.8–3.0), HBE: 1.1 (0.1–2.0)] but greater in the NW group [1.4 (0.02–2.8)] than in the ST group at 12 months. Generally, improvements in functional performance were greater (P < 0.001–P < 0.03) after NW compared with HBE and ST at all follow‐up time points. Furthermore, NW was superior (P < 0.01) to HBE for improving vigorous physical activity and to both ST and HBE for improving (P < 0.01) mental health. These data suggest that NW is the recommended exercise modality compared with ST and HBE.     

A randomized controlled trial for the effect of passive stretching on measures of hamstring extensibility, passive stiffness, strength, and stretch tolerance

To measure hamstring extensibility, stiffness, stretch tolerance, and strength following a 4-week passive stretching program. Randomized controlled trial. Twenty-two healthy participants were randomly assigned to either a 4-week stretching program consisting of 4 hamstring and hip stretches performed 5 times per week, or a non-stretching control group. Hamstring extensibility and stiffness were measured before and after training using the instrumented straight leg raise test (iSLR). Stretch tolerance was measured as the pain intensity (visual analog scale; VAS) elicited during the maximal stretch. Hamstring strength was measured using isokinetic dynamometry at 30 and 120° s⁻¹. Hamstring extensibility increased by 20.9% in the intervention group following 4 weeks of training (p < 0.001; d = 0.86). Passive stiffness was reduced by 31% in the intervention group (p < 0.05; d = −0.89). Stretch tolerance VAS scores were not different between groups at either time point, and no changes were observed following training. There were no changes in hamstring concentric strength measured at 30 and 120° s⁻¹. Passive stretching increases hamstring extensibility and decreases passive stiffness, with no change in stretch tolerance defined by pain intensity during the stretch. Compared to previous research, the volume of stretching was higher in this study. The volume of prescribed stretching is important for eliciting the strong clinical effect observed in this study.     

Shock wave application for chronic plantar fasciitis in running athletes. A prospective,randomized, placebo-controlled trial

BACKGROUND: Recent articles have reported success with repeated low-energy shock wave application for treatment of chronic plantar fasciitis in runners. HYPOTHESIS: Shock wave treatment for chronic plantar fasciitis is safe and effective. STUDY DESIGN: Prospective, randomized, placebo-controlled trial. METHODS: Forty-five running athletes with intractable plantar heel pain for more than 12 months were enrolled; half were assigned to a treatment group that received three applications of 2100 impulses of low-energy shock waves, and half received sham treatment. Follow-up examinations were performed at 6 months and at 1 year by a blinded observer. RESULTS: After 6 months, self-assessment of pain on first walking in the morning was significantly reduced from an average of 6.9 to 2.1 points on a visual analog scale in the treatment group and from an average of 7.0 to 4.7 points in the sham group. The mean difference between groups was 2.6 points. After 12 months, there was a further reduction of pain in both groups, to an average 1.5 points in the treatment group, and to 4.4 points in the sham group. CONCLUSION: Three treatments with 2100 impulses of low-energy shock waves were a safe and effective method for treatment of chronic plantar fasciitis in long-distance runners.     

Functional biomechanical deficits in running athletes with plantar fasciitis.

Plantar fasciitis is a relatively common injury that occurs in running athletes. The disease entity is a good example of an overloaded process of the plantar fascia at its calcaneal insertion. This study was designed to examine the strength and flexibility findings in the muscles that are put on tensile load during running, and which are responsible for controlling the forces on the foot during stance and pushoff, thus modifying the overload. Three groups of athletes underwent physical examination, including checking ankle range of motion in plantar flexion and dorsiflexion. Cybex peak torque measurements were taken at 60 and 180 deg/sec. The groups were a control group of 45 athletes with no symptoms, a group that included 43 affected feet with symptomatic plantar fasciitis, and a group that included the 43 unaffected contralateral feet. Analysis of data showed dynamic range of motion deficits in 38 of 43 affected feet, static range of motion deficits in 37 of 43 affected feet, deficits in peak torque at 60 deg/sec in 41 of 43 affected feet, and deficits in peak torque at 180 deg/sec in 37 of 43 affected feet. Statistical comparison of range of motion showed that the group with symptomatic plantar fasciitis was significantly restricted compared to both control and unaffected contralateral feet groups. Statistical comparison of peak torque showed that the symptomatic plantar fasciitis group was significantly lower than both other groups at both velocities. This study documents strength and flexibility deficits in the supporting musculature of the posterior calf and foot that are affected by plantar fasciitis.(ABSTRACT TRUNCATED AT 250 WORDS)     

Pressure-relieving properties of various shoe inserts in older people with plantar heel pain

Plantar heel pain is one of the most common musculoskeletal conditions affecting the foot and it is commonly experienced by older adults. Contoured foot orthoses and some heel inserts have been found to be effective for plantar heel pain, however the mechanism by which they achieve their effects is largely unknown. The aim of this study was to investigate the effects of foot orthoses and heel inserts on plantar pressures in older adults with plantar heel pain. Thirty-six adults aged over 65 years with plantar heel pain participated in the study. Using the in-shoe Pedar(?) system, plantar pressure data were recorded while participants walked along an 8 m walkway wearing a standardised shoe and 4 different shoe inserts. The shoe inserts consisted of a silicon heel cup, a soft foam heel pad, a heel lift and a prefabricated foot orthosis. Data were collected for the heel, midfoot and forefoot. Statistically significant attenuation of heel peak plantar pressure was provided by 3 of the 4 shoe inserts. The greatest reduction was achieved by the prefabricated foot orthosis, which provided a fivefold reduction compared to the next most effective insert. The contoured nature of the prefabricated foot orthosis allowed for an increase in midfoot contact area, resulting in a greater redistribution of force. The prefabricated foot orthosis was also the only shoe insert that did not increase forefoot pressure. The findings from this study indicate that of the shoe inserts tested, the contoured prefabricated foot orthosis is the most effective at reducing pressure under the heel in older people with heel pain.     

Shoe‐mounted accelerometers should be used with caution in gait retraining

Real‐time biofeedback gait retraining has been reported to be an effective intervention to lower the impact loading during gait. While many of the previous gait retraining studies have utilized a laboratory‐based setup, some studies used accelerometers affixed at the distal tibia to allow training outside the laboratory environment. However, many commercial sensors for gait modification are shoe‐mounted. Hence, this study sought to compare impact loading parameters measured by shoe‐mounted and tibia sensors in participants before and after a course of walking or running retraining using signal source from the shoe‐mounted sensors. We also compared the correlations between peak positive acceleration measured at shoe (PPA_S) and tibia (PPA_T) and vertical loading rates, as these loading rates have been related to injury. Twenty‐four and 14 participants underwent a 2‐week visual biofeedback walking and running retraining, respectively. Participants in the walking retraining group experienced lower PPA_S following the intervention (P < 0.005). However, they demonstrated no change in PPA_T (P = 0.409) nor vertical loading rates (P > 0.098) following the walking retraining. In contrast, participants in the running retraining group experienced a reduction in the PPA_T (P = 0.001) and vertical loading rates (P < 0.013) after running retraining. PPA_S values were four times that of PPA_T for both walking and running suggesting an uncoupling of the shoe with tibia. As such, PPA_S was not correlated with vertical loading rates for either walking or running, while significant correlations between PPA_T and vertical loading rates were noted. The present study suggests potential limitations of the existing commercial shoe‐mounted sensors.     

Effects of rocker radii with two longitudinal bending stiffnesses on plantar pressure distribution in the forefoot

IntroductionOutsole parameters of the shoe can be adapted to offload regions of pain or region of high pressures. Previous studies already showed reduced plantar pressures in the forefoot due to a proximally placed apex position and higher longitudinal bending stiffness (LBS). The aim of this study was to determine the effect of changes in rocker radii and high LBS on the plantar pressure profile during gait.Method10 participants walked in seven shoe conditions of which one control shoe and six rocker shoes with small, medium and large rocker radii and low and high longitudinal bending stiffness. Pedar in-shoe plantar pressure measuring system was used to quantify plantar pressures while walking on a treadmill at self-selected walking speed. Peak plantar pressure, maximum mean pressure and force-time integral were analyzed with Generalized Estimated Equation (GEE) and Tukey post hoc correction (α = .05).ResultsSignificantly lower plantar pressures were found in the first toe, toes 2–5, distal and proximal forefoot in all rocker shoe conditions as compared to the control shoe. Plantar pressures in the first toe and toes 2–5 were significantly lower in the small radius compared to medium and large radii. For the distal forefoot both small and medium radii significantly reduced plantar pressure compared to large radii. Low LBS reduced plantar pressure at the first toe significantly compared to high LBS independent of the rocker radius. Plantar pressures in the distal forefoot and toes 2–5 were lower in high LBS compared to low LBS.ConclusionManipulation of the rocker radius and LBS can effectively reduce peak plantar pressures in the forefoot region during gait. In line with previous studies, we showed that depending on the exact target location for offloading, different combinations of rocker radius and LBS need to be adopted to maximize treatment effects.