Back and neck muscle activity in healthy adults during barefoot walking and walking in conventional and flexible shoes

Does an acute transition to different footwear conditions affect walking patterns in people with different experiences of minimalist footwear?

BACKGROUND

Minimalistic footwear provides adequate toe space, tripod function, improving foot function, muscle activation and stability during walking similarly to barefoot walking. Due to the increasing popularity of this specific footwear, there is a lack of research focusing on general users of minimalistic footwear.

RESEARCH QUESTION

Does annual walking in minimalistic footwear affect gait biomechanics?

METHODS

Cross-sectional study involving twenty participants in a minimalistic footwear group with both experience (MFE) and no experience (NMFE). Participants walked in three different conditions (barefoot, minimalistic, and neutral footwear) in the laboratory at normal human walking speed.

RESULTS

A significant main effect of groups regardless of footwear conditions show significantly greater values during walking in minimalistic footwear and barefoot in the stride length (p=0.035, p=0.003, respectively), and stride width (p=0.047, p=0.028, respectively) in the NMFE group compared to MFE group. The significant differences in the main effects of footwear regardless of experience were found in stance time (p<0.001), steps per minute (p<0.001), stride length (<0.001), foot adduction in TO (p<0.001), foot eversion angle in IC and TO (p<0.001, p<0.001, respectively), foot progression angle (p<0.001), ankle dorsiflexion angle in IC and TO (p<0.001, p<0.001, respectively), in ankle eversion angle in IC and TO (p<0.001, p<0.001, respectively), knee flexion angle in IC and TO (p<0.001; p<0.001, respectively), and in knee flexion range of motion (p<0.001).

SIGNIFICANCE

Based on our findings, barefoot walking should be used primarily during daily activities if the environment is conducive. Only one year of experience with minimalistic footwear seems insufficient and an intervention should be incorporated to change the gait pattern when transitioning to full minimalistic footwear walking.

Effect of Footwear Type on Biomechanical Risk Factors for Knee Osteoarthritis

BACKGROUND

Regular walking in different types of footwear may increase the mediolateral shear force, knee adduction moment, or vertical ground-reaction forces that could increase the risk of early development of knee osteoarthritis (OA).

PURPOSE

To compare kinematic and kinetic parameters that could affect the development of knee OA in 3 footwear conditions.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 40 asymptomatic participants performed walking trials in the laboratory at self-selected walking speeds under barefoot (BF), minimalistic (MF), and neutral (NF) footwear conditions. Knee joint parameters were described using discrete point values, and continuous curves were evaluated using statistical parametric mapping. A 3 × 1 repeated-measures analysis of variance was used to determine the main effect of footwear for both discrete and continuous data. To compare differences between footwear conditions, a post hoc paired t test was used.

RESULTS

Discrete point analyses showed a significantly greater knee power in NF compared with MF and BF in the weight absorption phase (P < .001 for both). Statistical parametric mapping analysis indicated a significantly greater knee angle in the sagittal plane at the end of the propulsive phase in BF compared with NF and MF (P = .043). Knee joint moment was significantly greater in the propulsive phase for the sagittal (P = .038) and frontal planes (P = .035) in BF compared with NF and MF and in the absorption phase in the sagittal plane (P = .034) in BF compared with MF and NF. A significant main effect of footwear was found for anteroposterior (propulsion, ↑MF, NF, ↓BF [P = .008]; absorption, ↑BF, MF, ↓NF [P = .001]), mediolateral (propulsion, ↑MF, NF, ↓BF [P = .005]; absorption, ↑NF, MF, ↓BF [P = .044]), and vertical (propulsion, ↑NF, BF, ↓MF [P = .001]; absorption, ↑MF, BF, ↓NF [P < .001]) ground-reaction forces. Knee power showed a significant main effect of footwear (absorption, ↑NF, MF, ↓BF [P = .015]; propulsion, ↑MF, NF, ↓BF [P = .039]).

CONCLUSION

Walking in MF without sufficient accommodation affected kinetic and kinematic parameters and could increase the risk of early development of knee OA.

Effects of barefoot vs. shod walking during indoor and outdoor conditions in younger and older adults

BACKGROUND

Gait stability and variability measures in barefoot and shod locomotion are frequently investigated in younger but rarely in older adults. Moreover, most studies examine gait measures in laboratory settings instead of real-life settings.

RESEARCH QUESTIONS

How are gait stability and variability parameters affected by footwear compared to barefoot walking in younger and older adults as well as under indoor vs. outdoor conditions?

METHODS

Healthy younger (<35 years) and older adults (>65 years) participated in the randomised within-subject study design. Participants conducted consecutive 25 m walking trials barefoot and with standardised footwear inside and outside. Inertial measurement units were mounted on the participant's foot and used to calculate local dynamic stability (LDS), velocity and minimal toe clearance (MTC), stride length and stride time, including variabilities for these parameters. Linear mixed models were calculated.

RESULTS

Data of 32 younger (17 female, 15 male, age: 30 ± 4 years) and 42 older participants (24 female, 18 male, age: 71 ± 4 years) were analysed. MTC variability was higher in shod conditions compared to barefoot (p = 0.048) and in outdoor conditions (p < 0.001). LDS was different between age groups (p < 0.001). Gait velocity and MTC were higher in shod and outdoor conditions (both p < 0.001). Stride length and time were higher in shod conditions (both p < 0.001) and different between outdoor vs. indoor (longer stride length and shorter stride time outdoor, both (p < 0.001) as well as age groups (shorter stride length (p < 0.021) and stride time in older adults (p < 0.001).

SIGNIFICANCE

Results suggest that gait stability and variability in older and younger adults are acutely affected by footwear vs. barefoot and indoor vs. outdoor walking conditions, indicating a high adaptiveness of these parameters to different experimental conditions. Consequently, future studies should be careful with generalising results obtained under certain conditions. Findings stress the clinical potential of barefoot walking.

The mechanical energetics of walking across the adult lifespan

PURPOSE

Understanding what constitutes normal walking mechanics across the adult lifespan is crucial to the identification and intervention of early decline in walking function. Existing research has assumed a simple linear alteration in peak joint powers between young and older adults. The aim of the present study was to quantify the potential (non)linear relationship between age and the joint power waveforms of the lower limb during walking.

METHODS

This was a pooled secondary analysis of the authors' (MT, KD, JJ) and three publicly available datasets, resulting in a dataset of 278 adults between the ages of 19 to 86 years old. Three-dimensional motion capture with synchronised force plate assessment was performed during self-paced walking. Inverse dynamics were used to quantity joint power of the ankle, knee, and hip, which were time-normalized to 100 stride cycle points. Generalized Additive Models for location, scale and shape (GAMLSS) was used to model the effect of cycle points, age, walking speed, stride length, height, and their interaction on the outcome of each joint's power.

RESULTS

At both 1m/s and 1.5 m/s, A2 peaked at the age of 60 years old with a value of 3.09 (95% confidence interval [CI] 2.95 to 3.23) W/kg and 3.05 (95%CI 2.94 to 3.16), respectively. For H1, joint power peaked with a value of 0.40 (95%CI 0.31 to 0.49) W/kg at 1m/s, and with a value of 0.78 (95%CI 0.72 to 0.84) W/kg at 1.5m/s, at the age of 20 years old. For H3, joint power peaked with a value of 0.69 (95%CI 0.62 to 0.76) W/kg at 1m/s, and with a value of 1.38 (95%CI 1.32 to 1.44) W/kg at 1.5m/s, at the age of 70 years old.

CONCLUSIONS

Findings from this study do not support a simple linear relationship between joint power and ageing. A more in-depth understanding of walking mechanics across the lifespan may provide more opportunities to develop early clinical diagnostic and therapeutic strategies for impaired walking function. We anticipate that the present methodology of pooling data across multiple studies, is a novel and useful research method to understand motor development across the lifespan.

Effect of footwear on intramuscular EMG activity of plantar flexor muscles in walking

One of the purposes of footwear is to assist locomotion, but some footwear types seem to restrict natural foot motion, which may affect the contribution of ankle plantar flexor muscles to propulsion. This study examined the effects of different footwear conditions on the activity of ankle plantar flexors during walking. Ten healthy habitually shod individuals walked overground in shoes, barefoot and in flip-flops while fine-wire electromyography (EMG) activity was recorded from flexor hallucis longus (FHL), soleus (SOL), and medial and lateral gastrocnemius (MG and LG) muscles. EMG signals were peak-normalised and analysed in the stance phase using Statistical Parametric Mapping (SPM). We found highly individual EMG patterns. Although walking with shoes required higher muscle activity for propulsion than walking barefoot or with flip-flops in most participants, this did not result in statistically significant differences in EMG amplitude between footwear conditions in any muscle (p > 0.05). Time to peak activity showed the lowest coefficient of variation in shod walking (3.5, 7.0, 8.0 and 3.4 for FHL, SOL, MG and LG, respectively). Future studies should clarify the sources and consequences of individual EMG responses to different footwear.

The influence of footwear on walking biomechanics in individuals with chronic ankle instability

BACKGROUND/PURPOSE

The effects of footwear on the walking kinematics, kinetics and electromyography (EMG) of individuals with chronic ankle instability (CAI) at different speeds are still unknown. The objective of this cross-sectional study was to evaluate the kinematic, kinetic and electromyography differences between shod and barefoot walking at comfortable (CW) and fast (FW) speeds in individuals with CAI.

METHODS

Twenty-one individuals with CAI walked on a 5-meter walkway shod and barefoot at CW and FW speeds. A force plate was used to record the ground reaction forces, a 3-D motion analysis system to record the lower limb kinematics and a surface EMG system to collect the gluteus medius, vastus lateralis, gastrocnemius lateralis, gastrocnemius medialis, peroneus longus and tibialis anterior muscles activity. The dependent variables were ankle and knee angles and moments and normalized muscle activity. The shod and barefoot data during CW and FW were compared using a one-dimensional non-parametric mapping analysis.

RESULTS

The main results of this study were that individuals with CAI exhibited more ankle dorsiflexion angle, knee extension and tibialis anterior muscle activation during the beginning of the stance phase during shod compared to barefoot walking. Also, the biomechanical effects of shoes are similar during walking at FW and CW.

CONCLUSION

The biomechanical deficits associated with CAI were partly attenuated during the shod compared to the barefoot condition and these effects were similar at CW and FW. These findings are compatible with the concept that locomotor interventions using suitable shoes may enhance gait abilities in individuals with CAI.

Minimal footwear improves stability and physical function in middle-aged and older people compared to conventional shoes

BACKGROUND

Effects of minimal shoes on stability and physical function in older people are under-researched. No studies have systematically explored effects of a range of minimal footwear features on these factors in older people.

METHODS

A within-participant repeated-measures design was used. Participants were subjected to thirteen footwear conditions: (i) barefoot, (ii) a conventional shoe, (iii) a control minimal shoe, (iv-xiii) minimal shoes differing from the control minimal shoe by one design feature. The outcomes were: (i) postural stability expressed with movement of the center of pressure (CoP) during standing (ii) dynamic stability expressed with the CoP movement during walking, (iv) physical function assessed with the Timed Up and Go test (TUG), and (iv) perceptions of footwear assessed with the Monitor Orthopaedic Shoes questionnaire. Linear Mixed Models were applied for statistical analyses.

FINDINGS

Twenty-two people participated in the study. Compared to the conventional shoe, participants: (i) were more stable during standing and walking in the majority of minimal shoes, and (ii) completed the TUG test faster when wearing the minimal shoe with wider sole. Compared to the control minimal shoe, participants: (i) completed the TUG test faster when wearing the minimal shoe with wider sole; and (ii) perceived features such as a split toe and a higher ankle collar as less fashionable and wearable.

INTERPRETATION

Wearing minimal shoes might be more beneficial for stability and physical function in older adults than wearing conventional shoes. The results will be highly valuable for the design of minimal footwear for older adults.

Barefoot vs common footwear: A systematic review of the kinematic, kinetic and muscle activity differences during walking

Habitual footwear use has been reported to influence foot structure with an acute exposure being shown to alter foot position and mechanics. The foot is highly specialised thus these changes in structure/position could influence functionality. This review aims to investigate the effect of footwear on gait, specifically focussing on studies that have assessed kinematics, kinetics and muscle activity between walking barefoot and in common footwear. In line with PRISMA and published guidelines, a literature search was completed across six databases comprising Medline, EMBASE, Scopus, AMED, Cochrane Library and Web of Science. Fifteen of 466 articles met the predetermined inclusion criteria and were included in the review. All articles were assessed for methodological quality using a modified assessment tool based on the STROBE statement for reporting observational studies and the CASP appraisal tool. Walking barefoot enables increased forefoot spreading under load and habitual barefoot walkers have anatomically wider feet. Spatial-temporal differences including, reduced step/stride length and increased cadence, are observed when barefoot. Flatter foot placement, increased knee flexion and a reduced peak vertical ground reaction force at initial contact are also reported. Habitual barefoot walkers exhibit lower peak plantar pressures and pressure impulses, whereas peak plantar pressures are increased in the habitually shod wearer walking barefoot. Footwear particularly affects the kinematics and kinetics of gait acutely and chronically. Little research has been completed in older age populations (50+ years) and thus further research is required to better understand the effect of footwear on walking across the lifespan.