The weekly recap of what is going on in the world of biomechanics.
Lower limb mechanics
This week, we will present two journal pre-proof papers that have recently been made available online by the Journal of Biomechanics concerning lower limb mechanics. The first one is discussing a novel approach to identify foot contact parameters in the field, the second one discusses the effects of marching with a load, like soldiers do, on the risk of knee osteoarthritis.
Foot contact identification using a single triaxial accelerometer during running:
For a lot of biomechanical research, we need to acquire datasets concerning foot contact parameters. These might be for example the contact-time, duration of the swing-phase or tibial speed at toe-off. One may record this data for example using marker based motion capturing or accelerometers. Two researchers from Drexel University (Pennsylvania) now tried to measure the foot contact using only one accelerometer on the distal tibia and compared the outcomes to a force-plate measurement. They found that the differences in foot contact time measured with both methods was less than 10ms in 183 out of 190 trials. So they concluded the method is a valid way to assess foot contact time in the field. It might be a promising method since the material requirements are comparably low, plus the device is wearable and therefore qualifies for field research. It would be interesting to see which further parameters are measurable with this approach.
Aubol, Kevin G.; Milner, Clare E. (2020): Foot contact identification using a single triaxial accelerometer during running. In: Journal of Biomechanics, S. 109768. DOI: 10.1016/j.jbiomech.2020.109768
Load Carriage Magnitude and Locomotion Strategy Alter Knee Total Joint Moment during Bipedal Ambulatory Tasks in Recruit-Aged Women:
In female soldiers, knee osteoarthritis (OA) appears to be prevalent. The long term effects of OA are pretty well known, and obvoiusly effort is being made to reduce its prevalence. Soldiers are often required to walk long distances beyond their normal gait velocity carrying heavy loads, known as marching. This is one proposed mechanism to explain the higher rate of OA in soldiers. A group of researchers from the US and UK now determined the knee total joint moment (KTJM) in healthy women during running and marching with an additional loading of up to 45% of their bodyweight. The KTJM was analyzed at heel strike and mid-stance. Interestingly, KTJM at heel-strike was greater when marching, but at mid-stance it was lower than in running. At mid-stance, the knee adduction moment percent (KAM%) contribution was greater for marching when compared to running. We know that the KAM% is an important marker in the OA-pathomechanism. The authors conclude, that with prolonged exposure the joint kinetics during marching appear to be deleterious.
Krajewski, Kellen T.; Dever, Dennis E.; Johnson, Camille C.; Rawcliffe, Alex J.; Ahamed, Nizam U.; Flanagan, Shawn D. et al. (2020): Load Carriage Magnitude and Locomotion Strategy Alter Knee Total Joint Moment during Bipedal Ambulatory Tasks in Recruit-Aged Women. In: Journal of Biomechanics, S. 109772. DOI: 10.1016/j.jbiomech.2020.109772.
2nd Part of the Sports Biomechanics Lecture Series
The second part of the ISBS Sport Biomechanics Online Lecture Series focused on cricket sports. The first of the two lectures was given by Dr. Paul Felton from Nottingham Trent University. In his pyramid shaped lecture, he started to explain in general terms: What is an impulse? What is inertia? What are body segments? From there, with the help of suitable experiments from physics, he makes a successful transition to the biomechanics of cricket bowling. Dr. Felton explains how science can be used to determine the best technique and individual variations. Check it out:
The second talk was given by the organizer of the series, Stuart McErlin-Naylor from the University of Suffolk. Here, he talks about the factors influencing cricket batting, the differences between men and women and how best to train these factors. We recommend watching both lectures in the right order! Watch here the second part:
You can follow lecture 4 (Dr. Johannes Funken: Long Jump with a Sport Prosthesis) live on 7th April 2020 at 10pm CET. Lecture 5 (Dr. Wouter Hoogkamer: Running Footwear and 2 Hour Marathon) will take place on 10th April 2020 at 3pm CET. Why don’t you set up an alarm clock here?
ESB Webinar Series
Did you know that the European Society of Biomechanics also hosts a free webinar series? But this started even before the big Corona pandemic in Europe. Here, renowned scientists explain how to use software such as SimVascular, OpenSim or, as in the latest issue, FEBio. This is a freely available finite element software that was developed specifically for solving problems in computer-aided biomechanics and biophysics. Last Monday Dr. Steve Maas explained in detail how to import CAD models and generate FE meshes, how to define the boundary conditions, material parameters and analysis settings, how to perform the analysis and how to visualize and animate the results. If you missed the tutorial, you can catch up on it by following this link: