Optimised techniques for arboreal activities

2018 | Alexander Laver and James Shippen, PhD, Tree Logic (Working with Coventry University, UK)

Recent advances in biomechanical motion analysis equipment has enabled the measurement of three-dimensional human movement within environments previously inaccessible. Previously motion analysis was performed using optical tracking equipment which, whilst accurate, was unsuitable for use outside and excluded its application to tree climbing. However motion capture equipment is now available which uses inertial tracking sensors and can operate in more realistic scenarios such as within the canopy of a tree. With this kit we are going to be able to map the movements of a tree climber as they climb, the data will then give us a body map showing the skeleton and muscle structure of the climber. We plan to record different access and climbing methods to analyse the effect on the climber body. We then plan to look at the task in the tree and work positioning options when undertaking those tasks. Having captured this information we can target a study, working with the climbers of mixed experience to see if climbers adapts their method to compensate for the stress and strains of the method or task. We hope this will guide us to recommend the best climbing methods for climbers to learn and master, to keep them fit and health and in the industry for a full and long career.

—-

Arborists always complain of suffering from musculoskeletal injuries caused by repetitive stretching and supporting large loads in contorted postures. The prolonged use of these techniques can result in muscle sprains and degenerative joint problems. This project has been investigating correlations between working practices and chronic injury rates to provide an evidence basis for the recommendation of safer working practices and improved healthcare for arborists. This in turn we would hope can guide better training and development of techniques for future generations, prompting longer working life and reducing the drain on our skilled workforce.

The project set out to establish whether there are there significant differences between arborists trained in traditional double rope DRT (moving rope), improved friction management DRT and modern developing SRT stationary rope techniques. Climbing tasks to include but not limited to: Ascent against stem, free hanging rope accent, movement in the canopy to pruning target, pruning cuts with a saw and descent from the tree. We hope to look at chainsaw work in time.

Coventry University’s biomechanics group has experience in applying motion capture methods across a broad spectrum of applications from sports performance optimisation, through product design to medical device analysis. The biomechanics group has developed software which is capable of analysing human motion and calculating the forces and torques developed within a person’s body during a diverse range of activities. Correlations will be calculated between loads occurring at major joints within the arborists’ bodies and the rate of musculoskeletal injuries.

Supporting this work, research through online surveys data from working arborists, to ascertain current working methods and the injuries they have suffered using these methods and whether they have made or have sort changes to reduce compounding injuries or problems. So far, all evidence has been anecdotal and we hope to gain some meaningful data to better understand the current problem.

Summer testing 2018

We scheduled two days of testing with Barbara May and James Shippen from Coventry University along with a climbing team. The first morning was spent testing the data capture equipment and setting it up to ensure it did not compromise climbers’ abilities to move freely or the climbing equipment function and safety. The afternoon was then spent in bench marking climbing ascent methods and techniques to start building up a data set to study. That evening we all met for a meal and a meeting to plan the following day.    We had proven that the concept worked well and could see the results on screen. On day two we expanded the data sets and looked at movement in the crown while branch walking.

The graph above shows loads on the climbing line for SRT in green and MRT in Red. We captured this data for all methods tested. In analysis we found we had one big issue. Up until this point the software and hardware had been used to study people in contact with the ground. The tree climber moving up the rope has their weight in the rope, harness, hands, and feet in passing contact with the tree. Tracking these loads to give us the full accurate picture of the muscle loads in the body and torques to the joints, was a major hurdle we are going to need to overcome. From the data sets we had captured we can model the methods and compare using nominal loads, but this relies on observation and experience of a climber connected to felling of the subjected loads moving around the system and body. This is going to demonstrate the theory but is not going to give us full reportable science, just anecdotal interpretation.

The project meeting the above challenge also got put on hold for few reasons beyond our control. Tree Logic suffered large losses from a series of break ins and robberies. During this time the research team at Coventry found themselves working remotely? with some big client projects as they lost their permanent laboratory space in a university restructure of facilities.

Picking the project back up again early this year following the need to concentrate on rebuilding my own business following the losses, we wrote and published a Survey to try and put some data to anecdotal reports from climbers that lead us to this starting this project. Through 18 questions we have made some clear discoveries and the full results will be publish this summer. At present we have over 325 response giving us a good broad data set. The main conclusions we can draw from this survey are (1) that tree climbers do indeed suffer from muscular and skeletal injuries, and (2) that there are also patterns of common areas where people get injured. We have been evaluating the results and we may try a follow up survey to see if we can dig deeper into these issues.

 

Year of Grant Awarded: 2018

Grant Program: Safe Arborists Technique Fund Grant Program

Grant Title: Optimised techniques for arboreal activities

Researcher: Alexander Laver

For more information on this project, contact the researcher via TREE Fund at treefund@treefund.org.