Jo Reeves received her PhD at University of Salford Manchester and two of her papers were highlighted as the IWB Quarterly Paper from her PhD work on foot orthoses:
What is something you want people to know about this project that you don’t get to share when writing the manuscript?
How grateful I am to my participants, friends and colleagues! For the long term effects of orthoses studies I appreciate everyone who made the effort to wear the orthoses every day. For the EMG study I am grateful to everyone who participated in the study involving fine-wire EMG, which is invasive, but especially thankful to those who let me practice on them while I was learning. Recording fine-wire EMG from the tibialis posterior (TP) is particularly challenging because there is approximately a 1 cm “safety window” between a neurovascular bundle and the tibia bone. It is also the deepest muscle of the lower limb at ~3 cm deep and the angle of insertion is key, else you end up cutting across the flexor digitorum longus. So I needed a fair bit of practice... To paraphrase Dr. Ruth Barn (@RuthBarn):
Who needs cadavers when you’ve got friends?
What was your biggest win in this project?
The angle of insertion for fine-wire EMG of TP was something I was struggling with for a while. I tried different variations on the technique I was initially taught, including inserting the needle while the ultrasound probe was still on the skin, however I found this very fiddly and didn’t have much success. I contacted Prof Juan Garbalosa at Quinnipiac University who had published using the technique before and arranged a visit to his lab. Prof Garbalosa showed me how he positions the participant’s leg so that it is flexed more than the other techniques and raised off the bed, supported by the knee of the person inserting the needle. In this way the needle casing can be placed on the lateral aspect of the leg opposite to the needle insertion site and so it is easier to visualise a slice through the leg and the correct angle of insertion. It was a game changer!
What was your biggest challenge/failure in this project?
I had collected a full data set of EMG and kinematics and kinetics for 5 participants and was looking back over the EMG data and noticed a problem with the TP EMG data. I had randomised the order of orthoses conditions, but in the majority of cases the amplitude was always highest in the first condition. When I was training with the fine-wire EMG I was told that the fine-wire signal amplitude might go down over time, but hadn’t thought enough about the problem until then, and nothing had been documented about the issue that I was aware of. I had to make changes to the protocol to keep the recording duration short.
What advice would you give to someone who might be about to undertake a similar project, that you have learned as a result of this project?
Not just for similar projects, but for any research, I think the problem I noticed of the possibility of your signal changing over time is a prime example of the importance of looking at your data as you go along, not just waiting until you’ve finished collecting data from all your participants to start some analysis. For anyone doing fine-wire EMG, particularly in dynamic activities, I believe it’s vitally important to consider this time issue and think about keeping protocols short, randomizing task order and/or building in regular normalisation contractions. From a spin off project from this work, we showed that fine-wire amplitude of the tibialis anterior recording during walking can reduce by 11% after just 25 minutes, without any concurrent change in surface EMG (Reeves, 2020).
Have the results of this paper/project lead you down a certain path, if so, can/will you elaborate?
For my first postdoc I went to work with Professor Linda McLean at the University of Ottawa, who is a renowned expert in fine-wire EMG. We conducted a project in which 20 healthy participants were instrumented with fine-wire and surface EMG electrodes at the biceps brachii bilaterally. Participants held a weight statically with one arm and with the other arm repeated dynamic elbow flexion/extension contractions. Each task was repeated for 30 s every five minutes over two hours. Fine-wire EMG amplitude attenuated faster during the dynamic than the isometric protocol, again without a change in the surface EMG. (Reeves, 2021). I would like to have the chance in future to explore this phenomenon further.
What is your favorite thing about doing biomechanics research?
Getting to work with people while discovering new things using cool tech (guess that’s three things!).
What is your ultimate biomechanics research goal?
The recent international Consensus for experimental design in electromyography (CEDE) project (Besomi 202, Besomi 2019) recognised that many recommendations have been made which lack empirical evidence. My goal is to build a research programme around improving EMG methodology and applications within clinical biomechanics.
About the author:
Jo completed her PhD in biomechanics at the University of Salford, UK on the effect of foot orthoses on muscle activity and morphology, foot biomechanics and skin sensitivity. During the latter part of her PhD Jo was based at the University of Guelph, Canada. In that time she was involved in a collaborative project with the University of Salford investigating how mechanoreceptors on the sole of the foot respond to loads similar to those experienced in walking and another study on the influence of texture on joint position sense. Jo completed her first postdoc at the University of Ottawa investigating EMG methodology as well as contributing to projects involving pelvic floor muscles. Recently Jo has been working on industry collaborations at the University of Exeter and University of Portsmouth, driving innovation on footwear and sports bras. As part of the Research Group in Breast Health at the University of Portsmouth Jo has been working on refining methods of analyzing breast biomechanics.
References
Reeves J, Starbuck C, Nester C: EMG gait data from indwelling electrodes is attenuated over time and changes independent of any experimental effect. Journal of Electromyography and Kinesiology 54: 2020.
Reeves J, McLean L: The influence of contraction type, prior performance of a maximal voluntary contraction and measurement duration on fine-wire EMG amplitude. Journal of Electromyography and Kinesiology 59: 2021.
Besomi M, Hodges PW, Clancy EA, et al: Consensus for experimental design in electromyography (CEDE) project: Amplitude normalization matrix. J Electromyogr Kinesiol 53: 2020.
Besomi M, Hodges PW, Van Dieën J, et al: Consensus for experimental design in electromyography (CEDE) project: Electrode selection matrix. J Electromyogr Kinesiol 48: 2019.