Validity and reliability of peak tibial accelerations as real-time measure of impact loading during over-ground rearfoot running at different speeds
Authors: Pieter Van den Berghe
Marc Leman
Dirk De Clercq
Joren Six
Joeri Gerlo
Journal: Journal of Biomechanics (2019)
Discipline: MOLECULAR BIOLOGY & GENETICS
Keywords: Impact; Running biomechanics; Tibial shock; Validation; Wearable.
Affiliations: Department of Movement and Sports Sciences, Ghent University, Belgium. Electronic address: ., IPEM, Department of Arts, Music and Theatre Sciences, Ghent University, Belgium., Department of Movement and Sports Sciences, Ghent University, Belgium.

Abstract:  Studies seeking to determine the effects of gait retraining through biofeedback on peak tibial acceleration (PTA) assume that this biometric trait is a valid measure of impact loading that is reliable both within and between sessions. However, reliability and validity data were lacking for axial and resultant PTAs along the speed range of over-ground endurance running. A wearable system was developed to continuously measure 3D tibial acceleration and to detect PTAs in real-time. Thirteen rearfoot runners ran at 2.55, 3.20 and 5.10 m¬∑s-1 over an instrumented runway in two sessions with re-attachment of the system. Intraclass correlation coefficients (ICCs) were used to determine within-session reliability. Repeatability was evaluated by paired T-tests and ICCs. Concerning validity, axial and resultant PTAs were correlated to the peak vertical impact loading rate (LR) of the ground reaction force. Additionally, speed should affect impact loading magnitude. Hence, magnitudes were compared across speeds by RM-ANOVA. Within a session, ICCs were over 0.90 and reasonable for clinical measurements. Between sessions, the magnitudes remained statistically similar with ICCs ranging from 0.50 to 0.59 for axial PTA and from 0.53 to 0.81 for resultant PTA. Peak accelerations of the lower leg segment correlated to LR with larger coefficients for axial PTA (r range: 0.64-0.84) than for the resultant PTA per speed condition. The magnitude of each impact measure increased with speed. These data suggest that PTAs registered per stand-alone system can be useful during level, over-ground, rearfoot running to evaluate impact loading in the time domain when force platforms are unavailable in studies with repeated measurements. 

Retracted: No

PubPeer comments:
 Figure 4. * Blue boxes: In the HE staining row, the OA panel appears to overlap with the OA+CNs panel.  , 
 Figure 6B, Bax panel. * Yellow and pink boxes: Lanes 3 (OA+CNs) and 4 (OA+BBR) appear to look very similar, in particular the top and lower parts. The bands themselves appear to show sharp edges at their top and bottom parts.  , 
 Figure 7A. * Red boxes: In the caspase-3 row, the OA+BBR and OA+BBR-loaded CNs panels appear to show an overlap * Green boxes: In the Bcl-2 row, the OA and OA+CNs panels appear to show an overlap  , 
 #3 Dear Bik, Thanks for your comment. We think this comment is almost the same as the first one. So we response to them together in the first comment. Thank you! Yours sincerely, Shiqing Liu #1 Dear Dr. Bik, Thank you for your interest in our research and your efforts to ensure the accuracy of scientific research. After receiving your query, we carefully checked our original data and experimental records. Regarding your first and third comments raised by Figure 4 and 7A, there were indeed overlaps in the HE images and the immunohistochemical images of caspase-3 and bcl-2 in OA, OA+CNs, OA+BBR, and OA+BBR-loaded CNs groups after carefully checked. These mistakes probably due to the same site of a sample was taken twice by carelessness and accidently saved in different groups. Improper images were used due to our unintentional errors. We also failed to discover the problems during the submission process. Under no circumstances will we intentionally falsify and tamper with experimental data to mislead reviewers and readers. We are so sorry about the lack of rigour or negligence. We will contact the editor of the journal to resubmit the corrected images. We will take this lesson as a valuable learning opportunity to do better in the future research work. Thanks again! Yours sincerely, Shiqing Liu #2 Dear Dr. Bik, Thank you for your comments. Regarding your comment on Figure 6B, Bax panel, we have conducted a careful and detailed check. We think that the western blotting band was too narrow during cutting, which causes the western blotting band to be located in the narrow area and lacks sufficient background. For the visual effect of the image, we may have selected a similar background for the 2nd and 4th protein bands of Bax, and it became blurred during the image conversion process. So it seems that the backgrounds of the 2nd and 4th protein bands of Bax have similarities. We think that the defects of the image did not affect the experimental results, and hope that our explanation would convince you. At the same time, if you think it is necessary, we will contact the editor of the journal to replace this image. Thanks again for your comment. Yours sincerely, Shiqing Liu ,