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From the ACSM mtg: Four Weeks Familiarisation To Simulated Barefoot Running Significantly Improves Running Economy Compared To Shod Running
Joe P. Warne, Giles D. Warrington
Quote:
Despite the increased popularity of barefoot (BR) and simulated barefoot running (SBR), the physiological responses to different footwear conditions is largely unexplored and the process of adaptation and familiarisation to BR or minimalist SBR remains to be determined. PURPOSE:The purpose of this study was to evaluate the effects of a 4 week familiarisation period of SBR (Vibram Five Fingers, VFF) on running economy (RE) and compare this to running in a traditionally shod (SR) condition.
METHODS:15 male national level middle distance athletes (age: 24 ± 4 yrs; stature: 177.2 ± 6.21 cm; mass: 67.99 ± 7.36 kg and VO2 max 70.2 ± 5.2 ml/kg/min) were recruited to participate in the study. Subjects completed two RE tests; 24 hours apart, in both the VFF or SR condition, in a random order (pre-test) at 11 and 13km/h. Oxygen uptake (VO2), blood lactate (Bla), heart rate (HR), and stride frequency (SF) were measured during each test. Subjects then completed a 4 week familiarisation period of running in VFF’s, before repeating the 2 running economy tests in a random order (post-test).
RESULTS:Following the 4 week familiarisation a significant improvement in RE was observed at both velocities in the VFF condition (p=0.006), the improvement in RE was 7.7% between the pre-test and post-test (46.34 ± 1.29 v 43.02 ± 1.1 ml/kg/min; p=0.006). There was also a non-significant improvement in RE of 2.4% in the SR condition between over time (47.52 ± 0.94 v 46.43 ± 0.88 ml/kg/min; p=0.087). At the pre-test, RE was 2.2% lower in the VFF compared to the SR condition but this was not found to be significant (p=0.231). In contrast, following the familiarisation period (post-test), when compared to shod RE was significantly improved in the VFF condition (p=0.006: 45.884 ± 42.69 v 42.69 ± 1.21 ml/kg/min: 7.5% difference). SF was significantly higher (2.5%) in the VFF condition across both time points (p=0.01).
CONCLUSIONS:The results of the current study support previous research suggesting that SBR improves running economy when compared to SR, which may in part be explained by a change in running mechanics associated with an increase in SF and consequent reduction in stride length. The study findings also suggest that being fully habituated to running in VFF’s may further improve RE in the VFF condition and to a lesser extent the SR condition also.
From the ACSM Mtg: Comparison of Physiological Variables During Barefoot and Shod Treadmill Running in Inexperienced Barefoot Runners
Joel R. De Paoli, Matt Lee, Marialice Kern,
Quote:
PURPOSE: To examine differences in physiological
variables between barefoot (BF) and shod (SH) treadmill running in a group of inexperienced BF runners.
METHODS: Twelve participants with no previous BF running experience (mean age 24.8 ± 0.9 yr; 6 males, 6 females) engaged in 6-minute running bouts of both BF and SH at 6 mph and 1% grade (randomly assigned). Oxygen consumption (VO2), heart rate (HR), respiratory exchange ratio (RER), pulmonary ventilation (VE), and Rating of Perceived Exertion (RPE) were recorded during both conditions. Video data was also collected to examine stride rate (SR) and stride length (SL). Data was averaged over the last 2 minutes of each condition. A 2 x 2 (sex x condition) repeated measures ANOVA was used to examine differences in variables between
sex and conditions. A significance level of 0.05 was used for all tests.
RESULTS: The ANOVA revealed significant main effects of condition on VO2, VE, RER, SL, and SR. This was such that VO2, VE, and RER were lower during BF compared to SH (34.5±1.0 vs. 36.1±0.9 ml/kg/min, 55.3±4.0 vs. 58.8±4.2 liters/min and 0.92±0.1 vs. 0.94±0.02, respectively). Additionally, SL was lower (0.89±0.02 vs. 0.97±0.01 m) and SR was greater (181.0±3.6 vs. 166.4±2.7 strides/min) during BF compared to SH. Furthermore, there was a sex x condition interaction on HR such that HR was greater during BF in females (177.0±3.2 vs. 172±3.5 bpm), while it was lower during BF in males (159.2±2.7 vs. 164±1.7 bpm). Lastly, there was a trend for a main effect of condition on RPE such that it was lower during BF (11.6±0.3 vs. 12.3±0.4; p=0.086). Overall, the VO2 of running was 4.2% lower during BF compared to SH (males: 4.5%; females: 3.9%).
CONCLUSIONS: This data suggests that barefoot running is more economical than shod running in inexperienced barefoot runners. Additionally, BF results in shorter strides and a greater stride frequency, giving further merit to the notion that the economical differences, in part, result from the kinematic changes that occur when running barefoot. The different responses of HR between sexes during BF and SH warrants further investigation.
From the ACSM Mtg: Comparison of Metabolic and Biomechanical Factors of Running Economy in Minimalist versus Conventional Running Shoes
Joseph R. Bootier, Lauren S. Morimoto, Wanda Boda, Bulent Sokmen, Jordan S. Smith.
Quote:
Running economy is determined by biomechanical and metabolic efficiency. Decreases in stride length (SL), increases stride frequency (SF), and decreases in VO2 at a given workload have been related to improved economy in running. Minimalist running shoes (MRS) have flooded the market and shoe companies claim that they improve running economy when compared with conventional running shoes (CRS).
PURPOSE: To test claims made by a MRS company that running in their shoes improves economy when compared to running in CRS.
METHODS: A randomized, continuous treadmill running protocol was completed by ten trained runners (18-35 yrs) for each footwear condition. VO2 measurements were continuously collected during three submaximal stages. Each stage was five minutes in duration (6, 7.5 & 9 mph) with three-minute walking recoveries between each stage in order to ensure steady state VO2. Saggital plane kinematic data were collected at 210FPS using a high speed Casio video camera. Kinematic data were analyzed using KA Pro video analysis software. VO2 data from CRS and MRS shoe conditions were compared using a 2x3 ANOVA. Delta efficiency was calculated for CRS and MRS and correlated to stride length in meters (m) and stride frequency in steps per minute (SPM).
RESULTS: The metabolic energy consumption (VO2) in MRS was lower than in CRS at 6 mph (33.3 vs. 33.8 ml•kg•min-1), 7.5 mph (40.0 vs. 41.2 ml•kg•min-1), and 9 mph (48.3 vs. 49.6 ml•kg•min-1) but the results were not significant (p<0.94). Average delta efficiency in the MRS condition was slightly higher (15.08%) than that of the CRS (14.79%) condition. A moderate correlation was found between SF (173.3 SPM, r= 0.31), SL (0.89 m, r= -0.32) and delta efficiency in the CRS condition. A slightly stronger moderate correlation was found between SF (174.9 SPM, r= 0.40), SL (0.90 m, r= -0.36) and delta efficiency in the MRS condition.
CONCLUSION: Although there were trends toward improved running economy, our study results showed no significant differences in running economy between CRS and MRS conditions in trained runners.
From the ACSM Mtg: Adaptive Changes In Plantar-flexor Performance Following A Transition From Shod To Barefoot Running
Sachithra Samarawickrame, Rami Hashish, Kush Gaur, George Salem
Quote:
An estimated 10-20% of the American population are regular shod runners, 25% of whom are injured at any given time. Recent anecdotal reports substantiate a claim first proposed by Robin and Hanna (1987) that habitual barefoot runners have reduced lower-extremity injury rates compared to their shod counterparts. As a result, there has been a steady increase in the number of habitually shod runners who have switched to barefoot running. However, no study to date has examined the long-term adaptive changes in lower limb muscle performance when experienced shod runners transition to barefoot running. A pilot study was conducted to demonstrate the changes in ankle plantar-flexor peak torque (PT) and peak rate of torque development (RTD) in two habitually shod recreational runners who progressively transitioned into barefoot running over an 8-week period.
PURPOSE: To compare the post-exertion decline of ankle plantar-flexor PT and RTD between two running conditions - a novel barefoot condition and a post-transition barefoot condition.
METHODS: Two habitually shod runners (26-year-old female and 34-year-old male) were tested for PT and RTD at 10° plantar-flexion on a dynamometer, before and after a bout of running (defined as 20% of their typical daily running distance). Dynamometry was repeated after an 8-week transition period.
RESULTS: In the novel barefoot condition, PT declined 38-45% (24N.m, 39N.m) for the female and male subject respectively. Post-transition, the PT declined only by 22-26% (17N.m, 25N.m) after exertion. The plantar-flexors demonstrated an overall improvement of 32.5% (Cohen’s D Effect Size (ES): 2.12) in resistance to the exertion related decline in PT. In the novel barefoot condition, RTD declined 30-43% (42N.m/s, 59N.m/s). Post-transition, the RTD declined only by 20-29% (24N.m/s, 34N.m/s). The overall improvement of the resistance to the post-exertion decline of RTD was 42.8% (ES: 4.34).
CONCLUSION: There is evidence of adaptive improvements in the performance parameters of the plantar-flexors following a transition to barefoot running. This exploratory study will inform the design of expanded prospective studies on the transition from shod to barefoot running, ultimately leading to the formulation of recommendations on the benefits/risks of transitioning to barefoot running.
From the ACSM Mtg: Adaptation Of Contact Dynamics Following An Eight-week Transition From Shod To Barefoot Running
Rami Hashish, Sachithra Samarawickrame, Kush Gaur, George Salem,
Quote:
PURPOSE: Epidemiological studies suggest that 70 percent of the United States’ eleven million adult shod (SH) runners will sustain a yearly overuse injury - predominantly in the lower extremity. An increasing number of distance runners are transitioning to barefoot (BF) on the premise that the associated forefoot initial contact (IC) reduces the loading rate (LR), and thus potential for overuse injuries. However, the spatiotemporal characteristics of novice BF running are also associated with an increase in leg stiffness, which is a risk factor for knee injury. Therefore, the purpose of this exploratory investigation was to examine the effect of an eight-week transition from SH to BF running on this paradox.
METHODS: Kinematics and three-dimensional kinetics were collected on two habitually SH distance runners performing over-ground SH running at their self-selected speed and BF running at a matched speed. These runners were measured again following an eight-week transition to BF running consisting of a weekly incremental increase in BF running percentage. Loading rate was quantified as the derivative between initial loading (200 N) and the impact transient. Leg stiffness was modeled according to McMahon and Cheng (1990). Absolute change and the associated effect sizes (ES; Cohen’s d) between the two conditions are reported for the various measures.
RESULTS: Relative to SH running, novice BF runners demonstrated an increase in ankle plantar flexion (-23.7o; ES 2.52), a reduction in LR (-65.6BW.s-1; ES 4.05), yet an increase in leg stiffness (1.0; ES 2.18). Following the transition period, there was a reduction in plantar flexion at IC (2.2o; ES 1.027), as well as a reduction in both LR (-57.4BW.s-1; ES 1.08) and leg stiffness (-4.4; ES 1.36).
CONCLUSIONS: Despite being able to adapt a forefoot IC and a reduction in LR, novice BF runners presented with an increase in leg stiffness during ground contact. This may be associated with an increase potential for boney injury and be indicative of an impaired, or un-practiced, movement strategy. However, following the transition, there was a marked reduction in both LR and leg stiffness, suggesting that these runners adapted their movement strategy and contact dynamics - potentially reducing their injury risk.
Metabolic Cost of Running Barefoot versus Shod: Is Lighter Better?
Franz, Jason R.; Wierzbinski, Corbyn M.; Kram, Rodger
Medicine & Science in Sports & Exercise.
Quote:
Purpose: Based on mass alone, one might intuit that running barefoot would exact a lower metabolic cost than running in shoes. Numerous studies have shown that adding mass to shoes increases submaximal oxygen uptake (V[spacing dot above]2) by about 1% per 100 grams per shoe. However, only two of the seven studies on the topic have found a statistically significant difference in (V[spacing dot above]2) between barefoot and shod running. The lack of difference found in these studies suggests that factors other than shoe mass (e.g. barefoot running experience, foot-strike pattern, shoe construction) may play important roles in determining the metabolic cost of barefoot vs. shod running. Our goal was to quantify the metabolic effects of adding mass to the feet and compare oxygen uptake and metabolic power during barefoot vs. shod running while controlling for barefoot running experience, foot-strike pattern and footwear.
Methods: 12 males with substantial barefoot running experience ran at 3.35 m/s with a mid-foot strike pattern on a motorized treadmill, both barefoot and in lightweight cushioned shoes (~150 g/shoe). In additional trials, we attached small lead strips to each foot/shoe (~150, ~300, ~450 g). For each condition, we measured subjects' rates of oxygen consumption and carbon dioxide production and calculated metabolic power.
Results: V[spacing dot above]2 increased by approximately 1% for each 100 g added per foot, whether barefoot or shod (p<0.001). However, barefoot and shod running did not significantly differ in V[spacing dot above]2 or metabolic power. A consequence of these two findings was that for footwear conditions of equal mass, shod running had ~3-4% lower V[spacing dot above]2 and metabolic power demand than barefoot running (p<0.05).
Conclusions: Running barefoot offers no metabolic advantage over running in lightweight, cushioned shoes.
British Olympic runners could run more economically by just taking off their trainers, say researchers at Northumbria University.
In new research, Dr Michael Wilkinson found that when runners who always wear shoes run barefoot they immediately alter their gait to that characteristic of habitual barefoot runners, and also use less oxygen during barefoot running compared to running with shoes at the same speed. This indicates greater running economy which is an important determinant of distance running performance, especially in elite runners.
Habitual barefoot runners have a distinctive running gait – using mid-foot landings, shorter stride lengths, faster stride rates, and less time in contact with the ground. They are also known to hit the ground with lower impact force and loading rates than runners who land on the rear foot in trainers. This cushions the force of landing, avoiding the discomfort associated with striking the ground heel-first common in runners who wear shoes.
In the study, a mix of 18 recreational and highly trained runners participated in a six-minute moderate running task both barefoot and in shoes on separate days. During the runs, oxygen uptake was measured to assess energy expenditure and gait was analysed using digitalised video footage.
The runners reduced their stride length and ground contact time, increased their stride rate and, on average, used less oxygen during barefoot compared to shod running at the same speed, indicating greater economy. The 6% improvement in economy was the same as that previously reported after a nine-week training programme for shoe-wearing runners, who also enjoyed a 3% improvement in running performance.
The results suggest that, by ditching their trainers, athletes new to barefoot running adopt a running style similar to experienced barefoot runners and enjoy an immediate and likely beneficial increase in running economy.
Dr Wilkinson is an expert in the physiology of exercise and a barefoot runner for more than six years, completing the Great North Run barefoot in 2011. He said: “There’s a difference between shod and barefoot running gaits that comes about from feeling the ground. The sensory feedback when running barefoot encourages runners to put their feet down more gently in an attempt to avoid the impact forces that would cause discomfort and are also linked to injury.
“We saw a significant saving in energy from taking off running shoes. There were also mechanical differences in the foot strike pattern, with those who usually strike the ground with their heel first when they run with shoes, altering their pattern and striking the ground with the more cushioned mid-foot instead when barefoot.”
Previous studies have found that populations who habitually run barefoot report a low prevalence of lower-limb injury, suggesting that plantar-sensory feedback (being able to feel the nature of the terrain and adjust the force your feet apply to the ground) plays an important role in safe running.
Dr Wilkinson and his colleague Phil Hayes will disseminate their research and the science behind barefoot running benefits to athletic groups in the North East this month.
Barefoot Running: Science and Practice will take place on Wednesday 18 July, 6pm-8pm, at Northumbria University’s award-winning new sport, teaching and research facility, Sport Central.
Dr Wilkinson added: “Running barefoot is a hot topic in both running and scientific communities at present. High profile scientific studies have been popularised by the media reporting potential benefits of running barefoot for injury reduction and performance improvement.
“However, there is much misinformation being broadcast on the internet and in running magazines about barefoot running, little of which is based on current evidence from scientific investigations.
“However, there is much misinformation being broadcast on the internet and in running magazines about barefoot running, little of which is based on current evidence from scientific investigations."
lol ... yeah right! who can spot the misinformation (and outright lies!) in this press release? Rather than be part of the solution, they are part of the problem!
__________________ Craig Payne
__________________________________________________ ___________________________________ Follow me on Twitter | Run Junkie God put me on this earth to accomplish a certain number of things - right now I am so far behind, I will never die.
lol ... yeah right! who can spot the misinformation (and outright lies!) in this press release? Rather than be part of the solution, they are part of the problem!
__________________ Craig Payne
__________________________________________________ ___________________________________ Follow me on Twitter | Run Junkie God put me on this earth to accomplish a certain number of things - right now I am so far behind, I will never die.
The study analyzed the kinematics of each runner, the calories spent and the oxygen used while the person ran barefoot versus with cushioned shoes.
Researchers are still analyzing data, but the report is starting to take shape, and already Vincent has been surprised by the results.
What they have seen is that, overall, there was no significant difference in caloric expenditure, oxygen use or running technique in a person’s barefoot run versus his or her shod run.
“That was kind of in contrast to what I expected,” Vincent said. “That was really surprising to me.”
Vincent had expected to find that barefoot running was more efficient in terms of calories and oxygen use.
Here is an article written in The New York Times with references to this paper. Haven't got through all the comments from the zealots yet, but I bet they come out swinging
That article is actually a really good example of cherry picking; BUT, the comments are even worse - they mostly just showing their ignorance on how to actually read and understand research.
__________________ Craig Payne
__________________________________________________ ___________________________________ Follow me on Twitter | Run Junkie God put me on this earth to accomplish a certain number of things - right now I am so far behind, I will never die.
I have an issue with the actual research also - they tested barefoot, shoes, barefoot on treadmill covered with 10mm EVA; and barefoot on treadmill covered with 20mm EVA. They did not test shoes on treadmill with either thickness EVA.
In my humble opinion what this "only" suggests is that for barefoot running the optimum surface to run on is equivalent to their specific treadmill + 10mm EVA.
As you say Craig, more cheey picking and no actual facts.
Lower energy cost of running (Cr) has been reported when wearing minimal (MS) vs traditional shoes (TS) on level terrain, but the effect of slope on this difference is unknown. The aim of this study was to compare Cr, physiological, and kinematic variables from running in MS and TS on different slope conditions. Fourteen men (23.4 ± 4.4 years; 177.5 ± 5.2 cm; 69.5 ± 5.3 kg) ran 14 5-min trials in a randomized sequence at 10 km/h on a treadmill. Subjects ran once wearing MS and once wearing TS on seven slopes, from -8% to +8%. We found that Cr increased with slope gradient (P < 0.01) and was on average 1.3% lower in MS than TS (P < 0.01). However, slope did not influence the Cr difference between MS and TS. In MS, contact times were lower (P < 0.01), flight times (P = 0.01) and step frequencies (P = 0.02) were greater at most slope gradients, and plantar-foot angles - and often ankle plantar-flexion (P = 0.01) - were greater (P < 0.01). The 1.3% difference between footwear identified here most likely stemmed from the difference in shoe mass considering that the Cr difference was independent of slope gradient and that the between-footwear kinematic alterations with slope provided limited explanations.
Lower energy cost of running (Cr) has been reported when wearing minimal (MS) vs traditional shoes (TS) on level terrain, but the effect of slope on this difference is unknown. The aim of this study was to compare Cr, physiological, and kinematic variables from running in MS and TS on different slope conditions. Fourteen men (23.4 ± 4.4 years; 177.5 ± 5.2 cm; 69.5 ± 5.3 kg) ran 14 5-min trials in a randomized sequence at 10 km/h on a treadmill. Subjects ran once wearing MS and once wearing TS on seven slopes, from -8% to +8%. We found that Cr increased with slope gradient (P < 0.01) and was on average 1.3% lower in MS than TS (P < 0.01). However, slope did not influence the Cr difference between MS and TS. In MS, contact times were lower (P < 0.01), flight times (P = 0.01) and step frequencies (P = 0.02) were greater at most slope gradients, and plantar-foot angles - and often ankle plantar-flexion (P = 0.01) - were greater (P < 0.01). The 1.3% difference between footwear identified here most likely stemmed from the difference in shoe mass considering that the Cr difference was independent of slope gradient and that the between-footwear kinematic alterations with slope provided limited explanations.
The purpose of this study was to assess how the running economy of experienced runners was affected when wearing 4mm and 0mm heel to toe drop shoes as opposed to regular running shoes. Previous studies have shown that barefoot running and running in lower heel to toe drop shoes increases running economy (Squadrone & Galozzi, 2009). The participants (n=23; 18 male and 8 female) were subjected to 3 separate tests that were each 20 minutes. The tests were performed within 90 minute, the order randomized. During the first test, the subject ran for 20 minutes at a speed they would run at for 1 hour. During the second and third test, the subject ran at the same speed in their randomly chosen shoes. Gas analysis was used to measure VO2 in kilograms and measurements were taken one time per breath for 20 minutes with a Vacumed mini-CPX. Using one way repeated ANOVA, results were not significant (p>.05). The results of this study show that there was not a significant difference in running economy between running with 4mm or 0mm heel to toe drop shoes and running with regular running shoes.
My God the Church of Barefoot.Minimalism should just tap out now, not a great year for their cause in actual RESEARCH!
__________________
"If we all worked on the assumption that what is accepted as true is really true, there would be little hope of advance." - Orville Wright
I blogged about this study here. Read the analysis in the comments section for a good take on the study.
__________________ Craig Payne
__________________________________________________ ___________________________________ Follow me on Twitter | Run Junkie God put me on this earth to accomplish a certain number of things - right now I am so far behind, I will never die.
No Difference in Metabolic Efficiency in Barefoot and Shod Conditions in Experienced Mid-Forefoot Runners
Kevin R. Vincent, Cindy Montero, Bryan P. Conrad, Joseph Wasser, Clarissa Lomonaco, Matthew Martenson, Heather K. Presented at 2013 ACSM Mtg
Quote:
It is not yet clear whether metabolic efficiency is different in barefoot and shod conditions in experienced mid-forefoot runners.
PURPOSE : This study compared the oxygen cost, metabolic parameters and select biomechanical variables between barefoot and shod running in trained mid-forefoot runners (N=21).
METHODS : men and women (30.0±10.9 years; 82% men, 15.6% body fat) performed two separate 20 minute treadmill running bouts at ~77% of maximal heart rate. Rate of oxygen consumption (VO2), energy cost, fuel use and heart rate (HR) were collected continuously using a portable gas analyzer. Average exercise bout values, and values obtained at 3, 12, and 19 min were evaluated to determine whether condition differences occurred during the exercise bout. Three dimensional motion capture and force plates were used to determine kinematic and kinetic variables.
RESULTS: Participants ran at 185 ± 20 m/min for both conditions, at intensities corresponding to HR values of 146 bpm (shod) and 144 (barefoot). The oxygen cost area under the curve (AUC) values in the shod and barefoot conditions were 1461 ± 203 ml/kg*min and 1415 ± 222 ml/kg*min, respectively. The total energy expended in the shod and barefoot conditions was 974 ± 134 kJ and 979 ±142 kJ. The average nonprotein respiratory exchange ratios, proportions and amount of fat and carbohydrate used were not different between conditions. Cadence was 2.5% higher and stride rate was 3% (p<.05). Peak ground reaction forces were higher in the shod condition compared to the barefoot condition (1756 ± 310 N versus 1703 ± 285 N; p<.05), and the vertical displacement of the center of gravity was less in the barefoot condition by 0.5cm.
Discussion: In trained mid-forefoot runners experienced with barefoot running, there are not significant metabolic differences and fuel use patterns between shod and barefoot running conditions longer than a few minutes in duration. It is likely that experienced participants were able to titrate kinematics and muscle activation to standardize energy output and fuel use for a given running distance and speed irrespective of shoe wear. Sponsored by the UF Sports Performance Center, and UF Running Medicine Clinic.
Comparison of Running Efficiency Wearing the Vibram FiveFingers® and Conventional Running Shoes
Steve Cusack, Susan Kwiecien, Deborah Atwell, Laura D’Amore, Corynne Pereira, Kimberly Pereira, Stephanie Rude, John Wygand, RM Otto Presented at the 2013 ACSM Mtg
Quote:
The use of alternative footwear for activities of daily living, as well as recreational and sport participation is gaining popularity. A recent movement toward minimalist footwear, such as Vibram FiveFingers® (V5F) has its roots with barefoot locomotion. For individuals accustomed to a life of cushioned and raised heel footwear, the change may be traumatic, affect the biomechanics of locomotion and impact movement efficiency.
PURPOSE : Metabolic efficiency was evaluated to determine the acute and chronic (2 week adaptation period) effects of walking (80.4 m/min= W) and running (214.4 m/min = R) for subjects novice to wearing minimal footwear.
METHODS : 8 male and 6 female recreational athletes (age 22 ± 4 yrs), who were unfamiliar with wearing minimal footwear, were fitted for V5F and immediately performed the acute (A) trials of W and R with randomly assigned V5F footwear or the subject’s own running shoes (S) in a crossover design. After a 45 minute rest period, the crossover trials were conducted. Metabolic efficiency was obtained by open circuit spirometry at a 1% treadmill elevation. After a minimum 168 hour adaptation (14 days x ≥ 12 hrs/day) to minimal footwear, all subjects repeated the trials as part of the post-test.
RESULTS: For the 8 trials, VO2 (mL kg-1 min-1) was obtained for Pre S, Pre V5F, Post S and Post V5F (13.78±1.0, 13.49±1.0, 13.77±1.3, and 13.70±1.0) and (41.72±2.9, 41.24±3.1, 41.26±3.2, and 40.95±3.2) for W and R trials, respectively. There were no significant differences (P>.05) between V5F and S treatments in relation to VO2 , RR, VE, and HR within W and R trials, either acutely or following adaptation.
CONCLUSION: Adaptation to minimal footwear does not affect metabolic efficiency. The use of minimal footwear did not provide an advantage over standard running shoes despite a reduction in shoe mass (μ 217g). Chronic use of minimal footwear may provide alternative biomechanical stress of the lower extremity; however, the consequences are unknown.
Changes in Running Form and Economy in Trained Male Endurance Runners Switching to Barefoot Shoes
Alexander T. Sougiannis, Michael W. Olson, Juliane P. Wallace, Presented at 2013 ACSM Mtg
Quote:
Minimalist running has been suggested to decrease force of impact on the heel and allow the runner to transition to a more forefoot strike style of running. However, there are many opponents of minimalist running who claim that minimalist running alters the type and not the incidence of injuries. There are also speculations as to whether minimalist shoes actually improve running economy in comparison to traditional running shoes.
PURPOSE : The purpose of this study was to analyze the biomechanical and metabolic differences between minimalist shoes and traditional running shoes in a novice runner.
METHODS : In a pilot study, one subject performed three separate running trials; a VO2 max test, and two 30 min run tests at 2.4m*s-1; one with traditional running shoes (TS), one with minimalist running shoes (MS). Reflective markers were positioned on the right side of the subject to monitor kinematics using a multi-camera system. Sagittal plane kinematics were observed over each 30 min session for 10 s at 5, 15, and 25 min running intervals. Kinematics variables of interest were: average foot angle, average leg angle, average ankle angle, leg angle at initial foot contact (IC), foot angle at IC, and the ankle angle at IC. VO2 and RER were collected continuously using a Medical Graphics metabolic cart.
RESULTS: VO2/kg, VO2, and RER showed consistent values in the two shoe types (TS; VO2/kg: 24.69 ±5, VO2: 2116.3 ±621.5, RER: 0.97 ±0.035, MS; VO2/kg: 28.1 ±4.9, VO2: 2409.9 ± 427.2, RER: 0.96 ± 0.045). No between condition differences were observed in the kinematics. There was a difference within the MS at 25 min for foot angle IC as midfoot contact (2.3 ± 1.5º) with greater plantar flexion (95.8± 0.9º) gradually transitioned to a heel contact (11.5 ± 3.2º) with more ankle dorsiflexion (88 ± 3.5º) (t=0.011 and t=0.021 respectively). The trend of the variability of the ankle angle increased in both conditions denoting a function of task, but the linear trend for the foot angle continued in the MS condition (r2 = 0.88) but not in the TS condition (r2 = 0.08).
CONCLUSION: There are no significant changes in running economy with first time use of minimalist shoes. Kinematics data can be used to infer that novices to MS running can transition gait patterns during long duration runs, but these changes are highly variable and indicate a prolonged learning period.
Effect of Training in Minimalist Running Shoes on Running Economy
Kurt Van Wagenen, Brenda Benson, A. Wayne Johnson, Ulrike
Mitchell, Iain Hunter, Sarah Ridge. Brigham Young University, Presented at 2013 ACSM Mtg
Quote:
PURPOSE : The popularity of running in minimalist shoes raises questions about their effect on running economy (RE) as compared to running in traditional running shoes. It has been suggested that minimalist shoes allow for better metabolic economy during running. This study assessed whether or not RE was significantly different between groups training in traditional (Trad) running shoes and transitioning to minimalist (Min) shoes before and after 10 weeks of running.
METHODS : Twenty five runners who had been running a minimum of 15 miles per week with no previous training in minimalist running shoes participated in this study. Subjects were randomly assigned to either the control group, which ran in traditional running shoes, or the minimalist group, which transitioned to minimalist shoes over 10 weeks. All subjects performed sub-maximal VO2 tests in both traditional and minimalist running shoes before and after the 10 week training period. The order of testing conditions was randomized, with the first condition lasting 6 minutes and the second condition lasting 3 minutes. The treadmill pace was based on the subject’s 5K or 10K pace and held constant throughout the duration of the testing sessions. Average VO2 data over the last minute of running in each condition was analyzed using a 2-way repeated measures ANOVA with statistical significance set at p<.05.
RESULTS: There were no significant differences in RE between groups during either of the running conditions during pre- or post-testing (p=.159). There was a significant difference in RE between pre and post-testing in both shoe conditions (MinVO2pre=42.7±1.3, MinVO2post=39.9±1.1; TradVO2pre=42.3±1.4, TradVO2post=39.1±1.0; p=.01), regardless of group. However, the difference between both groups’ RE improvement was not statistically significant for either shoe condition (p=.196).
CONCLUSIONS : Overall, RE improved for both training groups, however there was no significant difference in the improvement of RE between groups in either shoe condition. Improvements in RE may have been caused by more consistent training as a result of participation in this study. In addition, the sub-maximal test may have allowed for more variability in individual intensities, and therefore, may not be as sensitive as VO2max testing in assessing changes in RE specific to shoe type.
Influence of Footwear Type on Running Economy
William A. Braun, FACSM, Sally Paulson, Todd Phillips, Mark Bittinger, Tom Krammer. Presented at 2013 ACSM Mtg
Quote:
Numerous claims of health-related benefits and new attention on orthopedic injury risk have accompanied the recent revival of barefoot and minimalist footwear options for running. Whether such footwear strategies may confer energy saving benefits is of interest.
PURPOSE : The study was designed to evaluate the effects of footwear choice (BF: barefoot; MF: minimalist footwear; RS: preferred running shoe) on running economy (RE) and related cardiorespiratory variables.
METHODS : Eight well-trained, female distance runners (age=20.1±1.4 yrs; mass=54.1±2.9 kg; height=1.64±0.06 m; body fat=18.3±2.9%) were recruited to participate in the study. Following two sessions for orientation to the treadmill and cardiorespiratory (CR) testing procedures, volunteers completed three RE tests on separate days with order counter-balanced. All runners had experience with BF running and were supplied with MF several weeks prior to experimental testing to become comfortable with their use. RE testing consisted of a 5 min warm-up at 2.24m.sec-1, followed by the 7-min test at 3.13 m.sec-1. Expired gases were analyzed from min 5-7 for determination of RE and related CR measures.
RESULTS: Respiratory exchange ratio, ventilation and respiratory rate were not found to be different across groups. However, RE, expressed as relative oxygen uptake per km, showed a trend (p=0.065) for oxygen uptake to be greater in the RS condition (RS: 204.51±2.84; MF: 198.21±3.04; BF: 193.26±3.62 ml.kg.km-1).
CONCLUSIONS: While performing sub-maximal, fixed-velocity running under differing shod conditions, RE and related CR measures were not found to be significantly altered in a sample of well-trained, female distance runners. However, the higher oxygen uptake trend in RS was associated with a ~5.8% greater oxygen uptake compared to BF. Such a difference could confer considerable energy conservation over a long distance run in a BF runner. Whether this would translate into performance enhancement should be investigated.
Running economy in shoes vs barefoot
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