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The objective of this study is to compare plantar loads during treadmill running and running on concrete and grass surfaces.
Crossover study design was used in the study.
A total of 16 experienced heel-to-toe runners participated in the study. Plantar loads data were collected using a Novel Pedar insole sensor system during running on the treadmill, concrete, and grass surfaces at 3.8m/s running speed and then analyzed.
Compared with running on the two other surfaces, treadmill running showed a lower magnitude of maximum plantar pressure and maximum plantar force for the total foot, maximum plantar pressure at two toe regions, and maximum plantar force for the medial forefoot region and two toe regions (p<0.0017). Treadmill running also showed a longer absolute contact time at two toe regions compared with running on the other two surfaces (p<0.0017).
Treadmill running is associated with a lower magnitude of maximum plantar pressure and a lower maximum plantar force at the plantar areas. These results suggest that the plantar load distribution in treadmill running is not the same as the plantar load distribution in running on overground surfaces. Treadmill running may be useful in early rehabilitation programs. Patients with injuries in their lower extremities may benefit from the reduction in plantar loads. However, the translation to overground running needs investigation.
One major drawback in measuring ground-reaction forces during running is that it is time
consuming to get representative ground-reaction force (GRF) values with a traditional force
platform. An instrumented force measuring treadmill can overcome the shortcomings
inherent to overground testing. The purpose of the current study was to determine the validity
of an instrumented force measuring treadmill for measuring vertical ground-reaction force
parameters during running.
Vertical ground-reaction forces of experienced runners (12 male, 12 female) were obtained
during overground and treadmill running at slow, preferred and fast self-selected running
speeds. For each runner, 7 mean vertical ground-reaction force parameters of the right leg
were calculated based on five successful overground steps and 30 seconds of treadmill
running data. Intraclass correlations (ICC(3,1)) and ratio limits of agreement (RLOA) were
used for further analysis.
Qualitatively, the overground and treadmill ground-reaction force curves for heelstrike
runners and non-heelstrike runners were very similar. Quantitatively, the time-related
parameters and active peak showed excellent agreement (ICCs between 0.76 and 0.95, RLOA
between 5.7% and 15.5%). Impact peak showed modest agreement (ICCs between 0.71 and
0.76, RLOA between 19.9% and 28.8%). The maximal and average loading-rate showed
modest to excellent ICCs (between 0.70 and 0.89), but RLOA were higher (between 34.3%
The results of this study demonstrated that the treadmill is a moderate to highly valid tool for
the assessment of vertical ground-reaction forces during running for runners who showed a
consistent landing strategy during overground and treadmill running. The high stride-to-stride
variance during both overground and treadmill running demonstrates the importance of
measuring sufficient steps for representative ground-reaction force values. Therefore, an
instrumented treadmill seems to be suitable for measuring representative vertical ground reaction.
What I have noticed about the difference between treadmill and overground running is that generally, unless the person is experienced in treadmill running, the treadmill causes shortening of the stride and a tendency toward flat foot or forefoot strike.
This would account for the reduced GRF noted in the 1st research abstract above.
Plus treadmills have more flexible, compliant landing surface than normal ground especially if the ground is concrete or tarmac, so resulting in force attenuation..
Regards Dave Smith
Descartes seems to consider here that beliefs formed by pure reasoning are less doubtful than those formed through perception.
Treadmill versus overground and barefoot versus shod comparisons of triceps surae fascicle behaviour in human walking and running
Neil J. Cronin, Taija Finni Gait & Posture; Article in Press
Studies of human locomotion are commonly performed on a treadmill or overground, as well as with or without footwear. These testing modalities have been suggested to influence kinematics, kinetics and/or spatio-temporal variables differently. However, it is unclear whether they influence contractile behaviour at the level of the muscle fascicles. This has major relevance because results from studies performed with different combinations of the testing modalities are often compared. The present study used ultrasound to examine fascicle behaviour of the medial gastrocnemius (MG) and soleus muscles of ten young, healthy males during walking and running on a treadmill and overground, as well as barefoot and shod. Barefoot conditions resulted in modestly shorter step durations than corresponding shod conditions, whereas no consistent temporal differences were observed between overground and treadmill locomotion. For both comparisons, no differences were observed in soleus or MG fascicle behaviour between corresponding conditions in walking or running, although soleus consistently exhibited smaller, lower velocity length changes than MG. It is concluded that the examined testing modalities are equally valid for studying muscle fascicle behaviour during locomotion. This conclusion is supported by a comparison of our data to the results of 16 previous studies that used various combinations of testing modalities; muscle fascicle behaviour is qualitatively similar between studies for a given muscle and gait.
► Triceps surae fascicle behaviour was examined in walking and running using ultrasound.
► Comparisons were made between treadmill – overground and barefoot – shod trials.
► No differences in fascicle behaviour were observed between testing modalities.
► Soleus consistently exhibited smaller, lower velocity length changes than MG.
Effect of overground vs treadmill running on plantar pressure: Influence of fatigue
José A. García-Pérez, Pedro Pérez-Soriano, Salvador Llana, Alfonso Martínez-Nova, Daniel Sánchez-Zuriaga Gait & Posture; Article in Press
•We compare the effect of treadmill vs overground during running fatigue on plantar pressure.
•Running on a treadmill increases contact time compared to running overground.
•Running on a treadmill modifies pressure distribution and reduces peak pressures.
•Fatigue reduces stride frequency and modifies peak pressures (lateral heel and hallux) and relative load (medial arch).
•The surface effect occurs independently of the fatigue state.
The differences produced when running on a treadmill vs overground may call into question the use and validity of the treadmill as a piece of equipment commonly used in research, training, and rehabilitation.
The aim of the present study was to analyze under pre/post fatigue conditions the effect of treadmill vs overground on plantar pressures. Twenty-seven recreational runners (17 men and 10 women) ran on a treadmill and overground at two speeds: S1=3.33m/s and S2=4.00m/s, before and after a fatigue protocol consisting of a 30-min run at 85% of their individual maximal aerobic speed (MAS). Contact time (CT in seconds), peak pressure (PP in kPa), and relative load (RL in %) were analyzed under nine foot zones of the left foot using an in-shoe plantar pressure device.
A two-way repeated measures ANOVA showed that running on a treadmill increases CT (7.70% S1 and 9.91% S2), modifies the pressure distribution and reduces PP (25.98% S1 and 31.76% S2), especially under the heel, medial metatarsals, and hallux, compared to running overground. Moreover, on both surfaces, fatigue (S2) led to a reduced stride frequency (2.78%) and reduced PP on the lateral heel and hallux (15.96% and 16.35%, respectively), and (S1) increased relative load on the medial arch (9.53%). There was no significant interaction between the two factors analyzed (surface and fatigue). Therefore, the aforementioned surface effect, which occurs independently of the fatigue state, should be taken into account when interpreting the results of studies that use the treadmill in their experimental protocols, and when prescribing physical exercise on a treadmill.
Running shoes have recently been designed to mimic barefoot walking or running, and they are marketed with promises that runners will benefit from the effects of
barefoot running. Studying gait analysis with particular running shoes is extremely important because the ankle and foot serve as the foundation of structural balance,
support, and propulsion. In this study, the knee and hip joint motions will be addressed while wearing Vibram FiveFinger and Nike Free Run shoes, which are designed to
imitate barefoot running while providing protection from the elements. The purpose of this current study was to investigate the movement kinematics in the hip and knee joint while running on the treadmill at 0%, 4%, and 8% inclines in the barefoot condition as well as in Nike Free Run and Vibram FiveFinger shoes. Five experienced distance runners with a heel strike landing style in the traditional cushioned shoe were selected to participate in the study. During the testing each participant ran at 3.0 m/s on a slope of 0%, 4% and 8% in all three types of footwear. A two-way repeated measures ANOVA test was conducted at α = 0.05 followed by a t-test with a Bonferroni adjustment if a significant difference was found. The results of the study showed a significant difference in slope was observed between the 0% incline and the 8% incline during the heel strike phase in the hip joint and the mid support phase of the knee joint, and a significant difference in footwear was found between the barefoot and Nike shoe during the mid support phase of gait in the hip joint. Also during the mid support phase of gait, a significant difference was found between the barefoot and Nike shoe as well as the Vibram and Nike shoe in the knee joint. No significant differences were found when comparing shoe or slope in regards to angular velocity in both hip and knee joints. The findings of this study show that when looking at the phases of the gait cycle, the mid support phase of gait is the most crucial phase of gait. The toe off phase was found to be the least important phase of gait to be examined. Running slope is important because the slope can affect the running kinematics when the gradient is substantial (0% to 8%). It is critical that when developing new footwear that the mid support phase should be the most
important phase of gait to be examined, particularly in respect to the knee joint.
Treadmills are often used by runners when weather conditions are adverse or a specific training effect is desired. Athletes might respond to fatigue differently when running on a treadmill compared with overground conditions, where pace is typically more variable. The purpose of this study was to measure changes in gait parameters over the course of a 10 km treadmill run. Fifteen male competitive runners ran at a constant pace for 10 km at 103% of season's best time on an instrumented treadmill with in-dwelling force plates, and data were analyzed at five distances. Kinematic data were derived from high-speed videography and results compared between the early and late stages. Prior to halfway, step length increased and cadence decreased, while during the latter stages there were significant decreases in impulse and maximum force. Contact time decreased and flight time increased continually, but otherwise most gait variables did not change. The changes in contact and flight times suggested athletes altered their gait so that more time was spent airborne to allow the treadmill to pass under them. In general, however, the runners maintained their techniques throughout the run. Constant pace treadmill running might therefore be useful with the aim of running for a particular distance and speed with a consistent technique unaffected by factors such as gradient or fatigue. However, the increase in flight time might have aided the runners due to the nature of treadmill running, and athletes and coaches should note that this training effect is impractical during overground running.
Instrumented treadmills are increasingly used in gait research, although the imposed walking speed is suggested to affect gait performance. A feedback-controlled treadmill that allows subjects to walk at their preferred speed, i.e. functioning in a self-paced (SP) mode, might be an attractive alternative, but could disturb gait through accelerations of the belt. We compared SP with fixed speed (FS) treadmill walking, and also considered various feedback modes. Nineteen healthy subjects walked on a dual-belt instrumented treadmill. Spatio-temporal, kinematic and kinetic gait parameters were derived from both the average stride patterns and stride-to-stride variability. For 15 out of 70 parameters significant differences were found between SP and FS. These differences were smaller than 1cm, 1°, 0.2Nm and 0.2W/kg for respectively stride length and width, joint kinematics, moments and powers. Since this is well within the normal stride variability, these differences were not considered to be clinically relevant, indicating that SP walking is not notably affected by belt accelerations. The long-term components of walking speed variability increased during SP walking (43%, p<0.01), suggesting that SP allows for more natural stride variability. Differences between SP feedback modes were predominantly found in the timescales of walking speed variability, while the gait pattern was similar between modes. Overall, the lack of clinically significant differences in gait pattern suggests that SP walking is a suitable alternative to fixed speed treadmill walking in gait analysis.
•We compared self-paced (SP) with fixed speed treadmill walking.
•The gait pattern was similar for SP and fixed speed walking.
•The walking speed varied more during SP walking.
•The time scale of walking speed variability was dependent on the SP mode.
Investigation of treadmill and overground running: Implications for the measurement of oxygen cost in children with developmental coordination disorder
L.C. Chia, M.K. Licari, K.J. Guelfi, S.L. Reid Gait & Posture; Article in Press
•We compare overground and treadmill running technique in children with DCD.
•This is important to validate laboratory studies of treadmill running.
•There are limited kinematic differences between overground and treadmill running.
•Treadmill running is appropriate for studies of the energy cost of running.
Differences in the kinematics and kinetics of overground running have been reported between boys with and without developmental coordination disorder (DCD). This study compared the kinematics of overground and treadmill running in children with and without DCD to determine whether any differences in technique are maintained, as this may influence the outcome of laboratory treadmill studies of running economy in this population. Nine boys with DCD (10.3±1.1 year) and 10 typically developing (TD) controls (9.7±1 year) ran on a treadmill and overground at a matched velocity (8.8±0.9km/h). Kinematic data of the trunk and lower limb were obtained for both conditions using a 12-camera Vicon MX system. Both groups displayed an increase in stance time (p<0.001), shorter stride length (p<0.001), higher cadence (p<0.001) and reduced ankle plantar flexion immediately after toe-off (p<0.05) when running on the treadmill compared with overground. The DCD group had longer stance time (p<0.009) and decreased knee flexion at mid-swing (p=0.04) while running overground compared to their peers, but these differences were maintained when running on the treadmill. Treadmill running improved ankle joint symmetry in the DCD group compared with running overground (p=0.019). Overall, these findings suggest that there are limited differences in joint kinematics and lower limb symmetry between overground and treadmill running in this population. Accordingly, laboratory studies of treadmill running in children with DCD are likely representative of the energy demands of running.
Epidemiological studies analyzing the prevalence of running injuries suggest that overuse injuries are a prominent complaint for both recreational and competitive runners. Excessive coronal and transverse plane motions of the ankle and tibia are linked to the development of a number of chronic injuries. This study examined differences in tibiocalcaneal kinematics between treadmill and overground running. Ten participants ran at 4.0 m.s-1 in both treadmill and overground conditions. Tibiocalcaneal kinematics were measured using an eight-camera motion analysis system and compared using paired samples t-tests. Of the examined parameters; peak eversion, eversion velocity, tibial internal rotation and tibial internal rotation velocity were shown to be significantly greater in the treadmill condition. Therefore, it was determined treadmill runners may be at increased risk from chronic injury development.
Gender and Age-Related Differences in Bilateral Lower Extremity Mechanics during Treadmill Running
Angkoon Phinyomark, Blayne A. Hettinga, Sean T. Osis, Reed Ferber PLOSOne Aug 2014
Female runners have a two-fold risk of sustaining certain running-related injuries as compared to their male counterparts. Thus, a comprehensive understanding of the sex-related differences in running kinematics is necessary. However, previous studies have either used discrete time point variables and inferential statistics and/or relatively small subject numbers. Therefore, the first purpose of this study was to use a principal component analysis (PCA) method along with a support vector machine (SVM) classifier to examine the differences in running gait kinematics between female and male runners across a large sample of the running population as well as between two age-specific sub-groups. Bilateral 3-dimensional lower extremity gait kinematic data were collected during treadmill running. Data were analysed on the complete sample (n = 483: female 263, male 220), a younger subject group (n = 56), and an older subject group (n = 51). The PC scores were first sorted by the percentage of variance explained and we also employed a novel approach wherein PCs were sorted based on between-gender statistical effect sizes. An SVM was used to determine if the sex and age conditions were separable and classifiable based on the PCA. Forty PCs explained 84.74% of the variance in the data and an SVM classification accuracy of 86.34% was found between female and male runners. Classification accuracies between genders for younger subjects were higher than a subgroup of older runners. The observed interactions between age and gender suggest these factors must be considered together when trying to create homogenous sub-groups for research purposes.
Self-paced time trials have long been used as an indicator of running performance. The purpose of this study was to examine if potential physiological and thermoregulatory differences between treadmill and track running would alter performance in a self-paced 10 km time trial. Ten (n = 10) recreationally-trained male distance runners (32 +/- 6 y, 177 +/- 6 cm, 76 +/- 11 kg, 14.4 +/- 4.5% body fat, 62.2 +/- 9.5 mL [middle dot] kg-1 [middle dot] min-1 VO2 peak) completed two 10 km time trials in a randomized, counter-balanced order on separate days: one on a treadmill at 1% grade (TM), and one on a 200 m indoor track (IT). Core temperature, skin temperature, and heart rate were continuously monitored during the run. 10 km run time was longer during the IT trial (41.66 +/- 5.86 min) than the TM trial (40.10 +/- 6.06 min; p < 0.001), despite a faster first km in IT (p = 0.029). There were no differences between TM and IT trials in HR (174 +/- 13 and 178 +/- 13 bpm, respectively; p = 0.846) or body core temperature (38.6 +/- 0.5 and 38.9 +/- 0.5 [degrees]C, respectively, p = 0.218). Skin temperature was higher in TM (35.1 +/- 2.5 [degrees]C) than IT (32.7 +/- 3.0 [degrees]C; p = 0.002). These data indicate that performance differences exist between a 10 km time trial performed on a treadmill versus an indoor track, potentially due to differences in pacing strategy or metabolic cost between the two conditions.
Minimalist running shoes are designed to induce a foot strike made more with the forepart of the foot. The main changes made on minimalist shoe consist in decreasing the height difference between fore and rear parts of the sole (drop). Barefoot and shod running have been widely compared on overground or treadmill these last years, but the key characteristic effects of minimalist shoes have been yet little studied. The purpose of this study is to find whether the shoe drop has the same effect regardless of the task: overground or treadmill running.
Twelve healthy male subjects ran with three shoes of different drops (0, 4, 8 mm) and barefoot on a treadmill and overground. Vertical ground reaction force (vGRF) (transient peak and loading rate) and lower limb kinematics (foot, ankle and knee joint flexion angles) were observed.
Opposite footwear effects on loading rate between the tasks were observed. Barefoot running induced higher loading rates during overground running than the highest drop condition, while it was the opposite during treadmill running. Ankle plantar flexion and knee flexion angles at touchdown were higher during treadmill than overground running for all conditions, except for barefoot which did not show any difference between the tasks.
Shoe drop appears to be a key parameter influencing running pattern, but its effects on vGRF differ depending on the task (treadmill vs. overground running) and must be considered with caution. Unlike shod conditions, kinematics of barefoot condition was not altered by treadmill running explaining opposite conclusions between the tasks.
Treadmill vs. Overground Running Gait During Childhood: a Qualitative and Quantitative Analysis
Adam Rozumalski, Tom F. Novacheck, Chad Griffith, Katie Walt, Michael H. Schwartz Gait and Posture; in press
•Instrumented treadmill running analysis was conducted on kids ages 6-18.
•Kinematics, kinetics and EMG were collected and compared to matched overground data.
•Kinematics collected in the two conditions were similar except at the feet.
•Kinetics collected in the two conditions showed important differences.
Conventional gait labs are limited in their ability to study running gait due to their size. There is no consensus in the literature regarding the ability to extrapolate results for adult treadmill running to overground. This comparison has not been studied in children. Twenty-four healthy children (mean age 11.7) ran overground at a slow running speed while motion capture, ground reaction force, and surface electromyography (EMG) data were obtained. The same data were then collected while participants ran for six minutes on an instrumented treadmill at a speed similar to their overground speed. The kinematic, kinetic, and EMG data for overground and treadmill running were compared. Sagittal plane kinematics demonstrated similar hip and knee waveforms with the exception of more knee extension just before toe off. Ankle kinematic waveforms were similar during stance phase but treadmill running demonstrated decreased dorsiflexion during swing. Kinetic data was significantly different between the two conditions with treadmill running having a more anterior ground reaction force compared to overground. Due to the numerous differences between overground and treadmill gait demonstrated in this study, it is felt that the use of an instrumented treadmill is not a surrogate to the study of overground running in a pediatric population. This data set will function as a normative data set against which future treadmill studies can be compared
[Purpose] The present study aimed to determine changes in muscle activity while moving on a treadmill at various speeds. [Subjects] The activities of the left vastus lateralis, vastus medialis, hip adductors, lateral head of gastrocnemius, medial head gastrocnemius, soleus, and tibialis anterior of 10 healthy male university students were analyzed.
[Methods] University students walked, jogged, and ran for 10 minutes each in random order, and then myogenic potentials were measured 10 minutes later for 30 seconds. The flexion angle of the lower limb upon initial contact, mid stance, and toe off were measured.
[Results] The average walking, jogging, and running speeds were 3.6 ± 0.4, 6.7 ± 0.6, and 10.4 ± 1.3 km/h, respectively. The average electromyographic activities of the vastus medial, tibialis anterior, medial head of gastrocnemius, and lateral head of gastrocnemius significantly differed. All muscles were more active during jogging and running than walking. Only the soleus was more active during running than walking, and the activities of the hip adductors and vastus lateralis did not significantly differ.
[Conclusion] Velocity is faster and the angles of the lower limbs and ground reaction force (GRF) are larger during running than walking. The vastus medialis and soleus worked more easily according to the angle of the knee joint, whereas the tibialis anterior worked more easily at faster velocities and the medial and lateral heads of the gastrocnemius worked more easily with an increased GRF.
Background Non-invasive evaluation of in-shoe foot motion has traditionally been difficult. Recently a novel ‘stretch-sensor’ was proposed as an easy and reliable method to measure dynamic foot (navicular) motion. Further validation of this method is needed to determine how different gait analysis protocols affect dynamic navicular motion.
Methods Potential differences in magnitude and peak velocity of navicular motion using the ‘stretch sensor’ between (i) barefoot and shod conditions; (ii) overground and treadmill gait; and/or (iii) running and walking were made in 26 healthy participants. Comparisons were made using paired t-tests.
Results Magnitude and velocity of navicular motion was not different between barefoot and shod walking on the treadmill. Compared to walking, velocity of navicular motion during running was 59% and 210% higher over-ground (p < 0.0001) and on a treadmill (p < 0.0001) respectively, and magnitude of navicular motion was 23% higher during over-ground running compared to over-ground walking (p = 0.02). Compared to over-ground, magnitude of navicular motion on a treadmill was 21% and 16% greater during walking (p = 0.0004) and running (p = 0003) respectively. Additionally, maximal velocity of navicular motion during treadmill walking was 48% less than walking over-ground (p < 0.0001).
Conclusion The presence of footwear has minimal impact on navicular motion during walking. Differences in navicular motion between walking and running, and treadmill and over-ground gait highlight the importance of task specificity during gait analysis. Task specificity should be considered during design of future research trials and in clinical practice when measuring navicular motion.
Kinetic comparison of walking on a treadmill versus over ground in children with cerebral palsy
Marjolein M. van der Krogt, Lizeth H. Sloot, Annemieke I. Buizer, Jaap Harlaar Jnl of Biomech; Article in Press
Kinetic outcomes are an essential part of clinical gait analysis, and can be collected for many consecutive strides using instrumented treadmills. However, the validity of treadmill kinetic outcomes has not been demonstrated for children with cerebral palsy (CP). In this study we compared ground reaction forces (GRF), center of pressure, and hip, knee and ankle moments, powers and work, between overground (OG) and self-paced treadmill (TM) walking for 11 typically developing (TD) children and 9 children with spastic CP. Considerable differences were found in several outcome parameters. In TM, subjects demonstrated lower ankle power generation and more absorption, and increased hip moments and work. This shift from ankle to hip strategy was likely due to a more backward positioning of the hip and a slightly more forward trunk lean. In mediolateral direction, GRF and hip and knee joint moments were increased in TM due to wider step width. These findings indicate that kinetic data collected on a TM cannot be readily compared with OG data in TD children and children with CP, and that treadmill-specific normative data sets should be used when performing kinetic gait analysis on a treadmill.
A Comparison of Variability in Spatiotemporal Gait Parameters between Treadmill and Overground Walking Conditions
John H. Hollman, Molly K. Watkins, Angela C. Imhoff, Carly E. Braun, Kristen A. Akervik, Debra K. Ness Gait & Posture; Article in Press
?Variability in gait parameters may differ between treadmill and overground walking.
?We examined stride-to-stride variability with Poincar? analyses.
?Mean values were equivalent between treadmill and overground walking.
?Short- and long-term variability indicators were reduced on the treadmill.
?Treadmill training may induce invariant gait patterns.
Motorized treadmills are commonly used in biomechanical and clinical studies of human walking. Whether treadmill walking induces identical motor responses to overground walking, however, is equivocal. The purpose of this study was to examine differences in the spatiotemporal gait parameters of the lower extremities and trunk during treadmill and overground walking using comparison of mean and variability values. Twenty healthy participants (age 23.8 ? 1.2 years) walked for six minutes on a treadmill and overground while wearing APDM 6 Opal inertial monitors. Stride length, stride time, stride velocity, cadence, stance phase percentage, and peak sagittal and frontal plane trunk velocities were measured. Mean values were calculated for each parameter as well as estimates of short- (SD1) and long-term variability (SD2) using Poincar? analyses. The mean, SD1, and SD2 values were compared between overground and treadmill walking conditions with paired t-tests (α = .05) and with effect size estimates using Cohen's d statistic. Mean values for each of the gait parameters were statistically equivalent between treadmill and overground walking (p > 0.05). The SD1 and SD2 values representing short- and long-term variability were considerably reduced (p < 0 .05) on the treadmill as compared to overground walking. This demonstrates the importance of consideration of gait variability when using treadmills for research or clinical purposes. Treadmill training may induce invariant gait patterns, posing difficulty in translating locomotor skills gained on a treadmill to overground walking conditions.
Biomechanical and perceived differences between overground and treadmill walking in children with cerebral palsy
Taeyou Jung, Yumi Kim, Luke E. Kelly, Mark F. Abel Gait and Posture; Article in Press
?We compared overground and treadmill walking in children with CP.
?We analyzed gait variables at a matched walking speed.
?Self-selected walking speeds were examined for perceived differences.
?Treadmill walking altered spatiotemporal and kinematic variables.
?Children with CP showed perceived differences during treadmill walking.
The treadmill is widely used as an instrument for gait training and analysis. The primary purpose of this study was to compare biomechanical variables between overground and treadmill walking in children with cerebral palsy (CP). Perceived differences between the two walking modes were also investigated by comparing self-selected walking speeds. Twenty children with CP performed both overground and treadmill walking at a matched speed for biomechanical comparison using a 3-D motion analysis system. In addition, they were asked to select comfortable and fastest walking speeds under each walking condition to compare perceived differences. Significant differences in spatiotemporal variables were found including higher cadence and shorter stride length during treadmill walking at a matched speed (for all, P < .003). The comparison of joint kinematics demonstrated significant differences between overground and treadmill walking, which showed increases in peak angles of ankle dorsi-flexion, knee flexion/extension, and hip flexion (for all, P < .001), increases in ankle and hip excursions and a decrease in pelvic rotation excursion while walking on treadmill (for all, P < .002). Comparison of perceived difference revealed that children with CP chose significantly slower speeds when asked to select their comfortable and fastest walking speeds on the treadmill as compared to overground (for both, P < .001). Our results suggest that these biomechanical and perceived differences should be considered when using a treadmill for gait intervention or assessment.
Here's the comment I left on Griff's website regarding treadmill vs overground running:
Originally Posted by Kevin Kirby
The one point that they didn't make in this article is that when running overground there is a headwind which tends to resist forward movement. This headwind is not present during treadmill running. This is the most likely reason why the running on a treadmill needs a 1% grade to match the metabolic cost of running the same velocity as overground.
Numerous studies have concluded that treadmill and overground running are, basically, kinetically and kinematically the same for experienced treadmill runners. In both overground and treadmill running, if the velocity is constant, then the same work is being done (minus the headwind effect) since the acceleration of the runner is zero.
It's much like Einstein's relativity: running effort is directly correlated to the runner's velocity relative to the supporting surface, not relative to the observer's frame of reference relative to that runner. As long as the runner is moving at a constant velocity relative to their running surface's frame of reference, the work and effort of the runner should be the same (minus the headwind effect). In other words, the frame of reference for overground running is the ground, and the frame of reference for treadmill running is the treadmill belt.
Kevin A. Kirby, DPM
Adjunct Associate Professor
Department of Applied Biomechanics
California School of Podiatric Medicine at Samuel Merritt College
Treadmill Walking is not Equivalent to Overground Walking for the Study of Walking Smoothness and Rhythmicity in Older Adults
Brandi S. Row Lazzarini, Theodore J. Kataras Gait and Postue; Article in Press
•Trunk acceleration quantified gait smoothness and rhythmicity in older adults.
•Treadmill (TM) walking evaluated to determine equivalency to overground (OG).
•TM walking at OG speed improved rhythmicity and ML smoothness.
•TM walking at preferred TM speed worsened smoothness; probable speed effect.
•TM is not equivalent to OG for smoothness and rhythmicity studies of older adults.
Treadmills are appealing for gait studies, but some gait mechanics are disrupted during treadmill walking. The purpose of this study was to examine the effects of speed and treadmill walking on walking smoothness and rhythmicity of 40 men and women between the ages of 70-96 years. Gait smoothness was examined during overground (OG) and treadmill (TM) walking by calculating the harmonic ratio from linear accelerations measured at the level of the lumbar spine. Rhythmicity was quantified as the stride time standard deviation. TM walking was performed at two speeds: a speed matching the natural OG walk speed (TM-OG), and a preferred TM speed (PTM). A dual-task OG condition (OG-DT) was evaluated to determine if TM walking posed a similar cognitive challenge. Statistical analysis included a one-way Analysis of Variance with Bonferroni corrected post hoc comparisons and the Wilcoxon signed rank test for non-normally distributed variables. Average PTM speed was slower than OG. Compared to OG, those who could reach the TM-OG speed (74.3% of sample) exhibited improved ML smoothness and rhythmicity, and the slower PTM caused worsened vertical and AP smoothness, but did not affect rhythmicity. PTM disrupted smoothness and rhythmicity differently than the OG-DT condition, likely due to reduced speed. The use of treadmills for gait smoothness and rhythmicity studies in older adults is problematic; some participants will not achieve OG speed during TM walking, walking at the TM-OG speed artificially improves rhythmicity and ML smoothness, and walking at the slower PTM speed worsens vertical and AP gait smoothness.