Increased footwear comfort is associated with improved running economy - a systematic review and meta-analysis

Footwear with or without custom foot orthotics have the potential to improve comfort, but the link with running performance needs further investigation. We systematically reviewed the association of footwear comfort on running economy in recreational runners. Nine electronic databases were searched from inception to March 2020. Eligible studies investigated both direct outcome measures of running performance (e.g. running speed) and/or physiological measures (e.g. running economy (RE)) alongside comfort for each footwear condition tested. Methodological quality was assessed using the "Effective Public Health Practice Project" (EPHPP). RE during submaximal running was the most common physiological outcome reported in 4 of the 6 eligible studies. The absolute difference in RE between the most and least comfortable footwear condition was computed, and meta-analysis was conducted using a random effect model. The most comfortable footwear is associated with a reduction in oxygen consumption (MD: -2.06 mL.kg^-1.min^-1, 95%CI: -3.71, -0.42, P = 0.01) while running at a set submaximal speed. There was no significant heterogeneity (I² = 0%, P = 0.82). EPHPP quality assessment demonstrated weak quality of the studies, due to reporting bias and failing to disclose the psychometric properties of the outcome measures. It can be concluded with moderate certainty that improved RE in recreational athletes is associated with wearing more comfortable footwear compared to less comfortable footwear.HighlightsThis systematic review reports on the association of footwear comfort with running economy in recreational runners.Running economy during constant submaximal running is likely improved in recreational runners wearing more comfortable compared to less comfortable footwear.This finding is based on a meta-analysis, including four studies, showing a small but statistically significant decreased oxygen consumption at steady state speeds while wearing the most comfortable footwear.

Does a mobile-bearing, high-flexion design increase knee flexion after total knee replacement?

This prospective randomised controlled double-blind trial compared two types of PFC Sigma total knee replacement (TKR), differing in three design features aimed at improving flexion. The outcome of a standard fixed-bearing posterior cruciate ligament-preserving design (FB-S) was compared with that of a high-flexion rotating-platform posterior-stabilised design (RP-F) at one year after TKR. The study group of 77 patients with osteoarthritis of the knee comprised 37 men and 40 women, with a mean age of 69 years (44.9 to 84.9). The patients were randomly allocated either to the FB-S or the RP-F group and assessed pre-operatively and at one year post-operatively. The mean post-operative non-weight-bearing flexion was 107° (95% confidence interval (CI) 104° to 110°)) for the FB-S group and 113° (95% CI 109° to 117°) for the RP-F group, and this difference was statistically significant (p = 0.032). However, weight-bearing range of movement during both level walking and ascending a slope as measured during flexible electrogoniometry was a mean of 4° lower in the RP-F group than in the FB-S group, with 58° (95% CI 56° to 60°) versus 54° (95% CI 51° to 57°) for level walking (p = 0.019) and 56° (95% CI 54° to 58°) versus 52° (95% CI 48° to 56°) for ascending a slope (p = 0.044). Further, the mean post-operative pain score of the Western Ontario and McMaster Universities Osteoarthritis Index was significantly higher in the RP-F group (2.5 (95% CI 1.5 to 3.5) versus 4.2 (95% CI 2.9 to 5.5), p = 0.043). Although the RP-F group achieved higher non-weight-bearing knee flexion, patients in this group did not use this during activities of daily living and reported more pain one year after surgery.

Between-day repeatability of knee kinematics during functional tasks recorded using flexible electrogoniometry

The objective of this study was to assess the between-day repeatability of knee kinematics during activities of daily living recorded by electrogoniometry. One rater assessed the peak knee angles and knee excursion of 15 subjects during 13 activities twice with an average of 22 days (range 5-31) between the two assessments. The 15 subjects included four patients one year after total knee replacement (TKR) surgery, five patients before TKR surgery and six age-matched controls. Intra-class correlation coefficients and Bland and Altman coefficient of repeatability were derived to analyse the results. Only the most affected leg of the patients and the right leg of the controls were used for analysis. Different measures of repeatability showed different results. Intra-class correlation coefficients were higher than 0.75 for peak values of all functions except sitting down and rising from a standard chair. However, coefficients of repeatability ranged from 5.6 degrees for the loading response in level walking to 39.8 degrees for stepping out of a bath. Both of these values are higher than clinically significant changes seen after total knee surgery. It was concluded that for a single assessment on individual patients, the functional knee motion as performed in this study did not have sufficient repeatability. However, if the measurements are used to assess the average changes before and after surgery in a group of patients, the assessment of knee motion during activities such as level walking, and slope and stair ascending and descending were found to be sufficiently repeatable.

A prospective randomised double-blind study of functional outcome and range of flexion following total knee replacement with the NexGen standard and high flexion components

Modifications in the design of knee replacements have been proposed in order to maximise flexion. We performed a prospective double-blind randomised controlled trial to compare the functional outcome, including maximum knee flexion, in patients receiving either a standard or a high flexion version of the NexGen legacy posterior stabilised total knee replacement. A total of 56 patients, half of whom received each design, were assessed pre-operatively and at one year after operation using knee scores and analysis of range of movement using electrogoniometry. For both implant designs there was a significant improvement in the function component of the knee scores (p < 0.001) and the maximum range of flexion when walking on the level, ascending and descending a slope or stairs (all p < 0.001), squatting (p = 0.020) and stepping into a bath (p = 0.024). There was no significant difference in outcome, including the maximum knee flexion, between patients receiving the standard and high flexion designs of this implant.

The Footprint method to assess transmalleolar axis

Torsional deformities of the lower extremities are a common reason for an orthopaedic consultation and are also part of the evaluation of a patient in gait analysis. This study assessed the level of agreement between, and the repeatability of, the Footprint method and two other methods (Prone and Jig) of measuring the transmalleolar axis (TMA) clinically. The Footprint method measures the TMA as the patient sits by projecting the position of the malleoli downwards onto lined paper while the lines of the paper are aligned with the knee axis. The Prone method projects the position of the malleoli upwards onto the sole of the foot and this is related to the visually estimated knee axis. The Jig method uses a tropometer to relate the angle between the tibial tubercle and the two malleoli. Two assessors measured twelve subjects using the three methods and six subjects were re-measured approximately 1 week later for repeatability. There was poor agreement between the three methods but the Footprint method was the most repeatable (coefficient of repeatability: 5.4). One observer then assessed the repeatability of the effect of simulated equinus on the Footprint method in 10 normal subjects on 2 separate occasions 1 week apart. Equinus was obtained by having the subjects sit and firstly extend their knee and place the foot on the floor and secondly by placing the foot under consideration on a wedge. Both conditions introduced an offset into the measurement of the TMA when compared to the measurements with the ankle at neutral in the same subjects. The reliability of the Footprint method was then assessed using 10 inexperienced observers who measured nine normal subjects each on 2 separate occasions and their results compared with those from an experienced observer. The inexperienced observers were less repeatable than an experienced observer (coefficients of repeatability 9.2 and 6.9, respectively). We recommend that different methods of measuring TMA should not be used interchangeably in clinical practice. The Footprint method was the most repeatable of the three methods tested and can be used for patients who have fixed equinus but the measurement was less repeatable when used by inexperienced observers.

Muscle activity during gait initiation in normal elderly people

The purpose of this study was to describe the patterns of phasic muscle during gait initiation in normal elderly people. Bilateral surface EMG recordings were made of tibialis anterior, medial gastrocnemius and gluteus medius activity throughout gait initiation in 21 subjects. A variable expression of the onset muscle pattern is shown, with a tendency for muscle activity to be more variable in the preparatory phase. These results provide a baseline of normal gait initiation muscle activity against which to compare that of patients with gait initiation and balance difficulties.

Electrical stimulation of gluteus maximus in children with cerebral palsy: effects on gait characteristics and muscle strength

The purpose of this study was to determine whether electrical stimulation of the gluteus maximus would improve hip extensor strength, decrease excessive passive and dynamic internal hip rotation, and improve gross motor function in children with cerebral palsy (CP). Twenty-two ambulant children (15 females, 7 males, mean age 8 years 6 months, SD 2 years 9 months, aged 5 to 14 years) with diplegic (n = 14), hemiplegic (n = 7), and quadriplegic (n = 1) CP participated in this study. All were randomly assigned to either the stimulation or control group. The stimulation group (n = 11) received electrical stimulation of the gluteus maximus of the most affected legs for 1 hour a day, 6 days a week for a period of 8 weeks. Electrodes were applied proximally and distally over the gluteus maximus, with the active electrode initially positioned over the motor points. The control group (n = 11) did not receive any extra treatment. Measurements of hip extensor strength, gait analysis, passive limits of hip rotation, and section E of the Gross Motor Function Measure were made before and after treatment for both groups. Subjectively, 7 of the 11 parents thought that the treatment made a difference to their child. However, no statistically or clinically significant improvement was found in the stimulation group when compared with the control group.

Effect of foot orthoses on the kinematics and kinetics of normal walking gait

Despite their wide clinical application and success, our understanding of the biomechanical effects of foot orthoses is relatively limited. The aim of this study was to assess the effect of medially wedged and laterally wedged foot orthoses on the kinematics and joint moments of the rearfoot complex, knee, hip and pelvis and the ground reaction forces. The principal effect of the foot orthoses was on the rearfoot complex, where significant changes in joint rotations and moments were observed. Medially wedged orthoses decreased rearfoot pronation and increased the laterally directed ground reaction force during the contact phase, suggesting reduced shock attenuation. The laterally wedged orthoses increased rearfoot pronation and decreased the laterally directed ground reaction force during the contact phase, suggesting increased shock attenuation. The effects of the orthoses on knee, hip and pelvis kinematics were generally minimal. In view of the minimal effect the orthoses had on joints proximal to the foot, it is suggested that the orthoses may have additional effects on the passive and active soft tissues of the lower limb and it is these changes that result in the documented clinical success.

Multiple surface properties of worn RGP lenses and adhesion of Pseudomonas aeruginosa

The aim of this study is to determine rigid gas permeable (RGP) lens surface properties prior to and after wear that are influential on adhesion of Pseudomonas aeruginosa. After 10 and 50 days of wear and after end-stage use, lenses were collected for determination of physico-chemical surface properties and bacterial adhesion in a parallel plate flow chamber. Water contact angles on unused RGP lenses amounted 47+/-13 degrees and were affected by wear. In addition, %O at the lens surfaces, as determined by X-ray photoelectron spectroscopy increased after use for 10 and 50 days, but decreased after end-stage wear. The %N hardly increased after wear and, in line, SDS-PAGE did not indicate adsorbed proteins. The surface roughness of the lenses, as measured by atomic force microscopy amounted 9 nm after 10 and 50 days of use, but end-stage lenses were significantly rougher (48+/-23 nm). Moreover, initial deposition of P. aeruginosa #3 increased with increasing roughness for end-stage lenses. Multiple regression analysis, however, revealed that both physical and chemical surface properties were predictive for initial bacterial deposition to lens surfaces. After 10 days of wear, bacterial deposition was governed by the water contact angle, surface roughness, %O, %N, and %Si, while after 50 days of wear the surface roughness, %N, and %Si were found predictive for bacterial deposition. Initial bacterial deposition to end-stage lenses was solely dependent on the surface roughness. Summarizing, physico-chemical surface properties of RGP lenses change slightly during the first 10-50 days of wear, but end-stage lenses all had increased surface roughness, concurrent with increased bacterial adhesion.

Validity and reliability of a kinematic protocol for determining foot contact events

Timing of foot contact events provides important information for gait studies. The aim of the study is to validate the use of kinematic data, collected at 50 Hz to define foot contact events during gait initiation. Simultaneous kinetic and kinematic data recordings of four discrete foot contact events were made for normal adults. Raters were asked to estimate the timing of the events from kinematic data curves and these timings were compared with those derived from the kinetic data. For the four events, between 88 and 98% of all ratings were accurate to within 0.03 s. Inter-rater reliability was extremely high, reflecting the precision of the definitions used.

A methodology for studying the effects of various types of prosthetic feet on the biomechanics of trans-femoral amputee gait

This paper reports on a methodology developed for studying the effects of various types of prosthetic feet on the gait of trans-femoral amputees. It is shown that an analysis in three planes of motion of not only the prosthetic, but also the sound limb provides important information on the performance of prosthetic feet. Two male trans-femoral amputees were tested with four different prosthetic feet; the Springlite II, Carbon Copy III, Seattle LightFoot and the Multiflex foot. A detailed analysis of the results of one amputee and a summary of the most important results of a second subject is presented. The tests were carried out at normal (1.16 m s(-1)) and fast (1.56 m s(-1)) walking speeds. Three dimensional gait analysis was carried out to derive the time curves of the joint angles, intersegmental moments and power at the ankle, knee and hip joints at both the prosthetic and sound sides. A higher first peak of the ground reaction force at the sound side with the Seattle LightFoot compared to that with the Springlite II, may be the result of the lower late stance dorsiflexion angle with the former. Compared to the other two feet, the Carbon Copy III and the Springlite II showed higher prosthetic dorsiflexing moments and positive power at late stance, which could assist in the push-off. The 3D intersegmental loads at the ankle and knee can be used as a guide for design and for compilation of standards for testing of lower limb prostheses incorporating flexible feet.

The effect of wheelchair handrim tube diameter on propulsion efficiency and force application (tube diameter and efficiency in wheelchairs)

To determine the optimum tube diameter of a standard handrim-propelled wheelchair, the effect of tube size and shape on physiological and kinetic parameters was studied. Six able-bodied male subjects performed two tests on a wheelchair ergometer. Tests were performed against work loads comparable to every day use and with two different handrim tube diameters, a handrim with an oval 25 by 30 mm diameter (LR) and one with an 18 mm diameter (SR). The large tube diameter (LR) yielded slightly but significantly lower values for the physiological parameters. Gross mechanical efficiency was on average 7% for the LR and 6.3% for the SR. No significant results were found for force application parameters related to the direction of the applied force or the torque by the hand onto the handrim surface. As technique parameters could not explain the higher mechanical efficiency (ME) when using the LR, it is suggested that hand grip constraints in the push phase (finger flexor activity) might be responsible. Another possible explanation is that with a better hand grip using LR, less stabilization by the larger muscle groups at the elbow and shoulder is needed. The measured technique parameters seem to be determined by geometric constraints of the arm and shoulder. The technique requirements resulting from the forced trajectory of the propulsion movement are also likely to determine the technique parameters. Regarding the low mechanical efficiency of handrim propulsion, which is partly caused by the forced unfavorable trajectory of the hand, an alternative propulsion mechanism is suggested.