I do get a little tired of the running economy issue and foot strike pattern for a couple of reasons: Its been done to death (I have covered it here, here, here, here, here, here and here) and the fan boys get upset with me because the research which was not even done by me does not agree with what they have been preaching … go figure. Now we have another study that looked at kinematic and running economy changes following instruction similar to the Pose and/or Chi running method:
A novel running mechanic’s class changes kinematics but not running economy
Craighead, Daniel; Lehecka, Nick; King, Deborah L.
Journal of Strength & Conditioning Research; 14 April 2014
A novel method of running technique instruction, Midstance to Midstance Running (MMR), was studied to determine how MMR affected kinematics and running economy of recreational runners. An experimental pre post randomized groups design was used. Participants (n=18) were recreational runners who ran at least three days a week and 5 kilometers per run. All testing was done on a treadmill at 2.8 m[middle dot]s-1. The intervention group (n=9) completed eight weeks of instruction in MMR; the control group (n=9) continued running without instruction. The MMR group showed significant decreases in stride length (p=0.02) and maximum knee flexion velocity in stance (p=0.01), and a significant increase in stride rate (p=0.02) after the eight weeks. No significant changes were found in heart rate, rating of perceived exertion, or running economy. MMR was effective in changing stride rate and stride length, but was not effective in changing other kinematic variables such as foot contact position and maximum knee flexion during swing. MMR did not affect running economy. Evidence suggests that MMR may be an appropriate instructional method for recreational runners trying to decrease stride length and increase stride rate.
This study randomized a group of runners into a group that received MMR (Midstance to Midstance Running) and a group that did not. They measured baseline kinematic and running economy variables and followed them up after 8 weeks to repeat the measurements. The MMR instruction in the intervention group that was used is similar to that what is given in the Chi and Pose running methods, though I not sure what to make of what they claimed in the abstract presented on this study at the 2012 ASB meeting in which they just called the instruction as Pose running.
The study methods look reasonable though confusing in that they appear to have randomized the participants (good), but then stated that “runners where pair matched on gender, then age, weekly mileage and pace” – how can you both randomize and match them? (bad) – they should have clarified that as this can be a red flag (especially since the ASB abstract just mentioned matching and said nothing about randomizing); no comment was made about blinding the participants or of those carrying out the assessments (bad); I have no issues with the parameters they measured (good); there was justification for the 8 weeks and there was an a priori sample size calculation (good); I do however have a major problem with the nature of the analysis (bad), but that may not necessarily be fatal.
They reported that there was a change in the kinematic variables towards a decreased stride length and increased cadence and no improvements or changes in running economy following the instruction in MMR/Pose/Chi. Looking at the data presented in the tables, I concur that this is probably what they showed. HOWEVER, the statistical analysis done was not how you analyse a randomized trial. They used a within groups comparison rather than a between groups comparison. The whole idea of having a placebo or non-intervention group is to compare the outcomes between the two groups by statistical analysis (ie between groups comparison). The statistical analysis used by the authors looked at the baseline and follow up measures in each of the groups (ie a within groups comparison). This probably should not have got through the peer review and editorial process based on this. For more, see the consensus statement from the CONSORT group on the transparent publishing of trials and any textbook on the analysis of trials – they all say the same thing. However, in the above study if they had done the appropriate analysis, the results probably would have stood based on a visual inspection of the data in the tables.
As always, I go where the evidence takes me until convinced otherwise and within the context of the shortcomings of the nature of the analysis and the confusion regarding the allocation/randomization, this study confirms the previous studies that Pose running is not more economical, but can be used to shorten the stride length and increase the cadence (if that is what you want to do).
Craighead D, Lehecka N, & King DL (2014). A novel running mechanic’s class changes kinematics but not running economy. Journal of strength and conditioning research / National Strength & Conditioning Association PMID: 24736769