Why You Need to Know about Biomechanics

Why You Need to Know about Biomechanics

Do you know how much strain you put on your body when pushing, pulling, or lifting to move and handle patients with manual aids? Musculoskeletal disorders continue to be an issue among health personnel, and it is more important than ever that we realise that patient transfers present a serious risk of work injuries.

13. January 2020

By: Occupational Therapist, Pia Beck

Few will be able to answer the above questions with a confident 'yes'. But not knowing the answer to this question, also means not knowing whether a given patient transfer overloads our musculoskeletal system or not. Or framed differently, we do not know if we are putting ourselves at risk of attaining a work injury. This is where a basic understanding of biomechanics come into play.

The Large Muscles do (not do) the Heavy Lifting

For years we have known that manually lifting patients has put healthcare employees in great risk of acute injuries. Therefore, we have seen a slow transition away from lifting practices towards pushing, rolling, and pulling as a gentler way of moving and handling across healthcare sectors.

The reasoning goes, that when using correct technique, it is the large muscle groups in your legs that do the heavy work when pulling and pushing. But the fact is that it is only these muscles that start the movement. The rest is still done by the muscles in our arms, neck, shoulders, and lower back. Unless you have found some way of turning patients with your legs? (Seriously, if you have, I need to know…).

But if we have a look at the numbers for musculoskeletal disorders (MSB) among health personnel it becomes clear that we have not cracked the code to a sustainable work health and safety in the healthcare sector. According to The European Agency for Safety and Health at Work, 47 % of workers in human health and social work activities experienced back pain and 46 % experienced upper limb pain in the past 12 months. For example, a study from The Danish Working Environment & Health from 2018 exploring 39,000 workers showed that 37 % of nurses and 46 % of social and healthcare assistants experienced musculoskeletal pain (any type) every week (in comparison, the number was 32.5 % in the general working population). And looking at data from other countries, do not change the overall picture.

As such, the transition from lifting towards pulling and pushing has not been the success we would have liked it to be. Maybe it's time we give our approach to patient transfers an overhaul?

One way to do this is to give our healthcare professionals the skillset to make a competent decision when it comes to moving and handling. This decision must be made based on professional evaluations, rather than letting our personal beliefs such as "It won't happen to me" or “I won’t get injured” cloud our judgements.

What is Biomechanics?

Prepare for things to get boring - really boring! Biomechanics deals with the study of the musculoskeletal system using mechanical and physical measurement methods. It is used, for example, in connection with the investigation of causes of work injuries and when exploring max reaching distances and working loads. When evaluating whether a patient transfer is safe to do or not biomechanics becomes an essential tool.

But knowledge of biomechanical calculations is not a substantial part of most healthcare educational programs. Therefore, very few people know how great the strain on the lower back actually is, just when bending forwards even a little. Think of the times you have been washing dishes at your kitchen sink - after a short amount of time, you will notice that your lower back is tiring or even aching. 

People who experience acute work injuries are often surprised by how little it took. It might have been a task that they have done many times before that suddenly took an unexpected turn. Even the smallest change in posture, angle, or weight of the burden being handled can be too much. Biomechanical calculations can tell us if a task is too strenuous or not. And therefore, it is so important to know about it.

You might also like: The benefits of a Powered Turning Aid

What is a Biomechanical Calculation?

A biomechanical calculation is a method that calculates how large the load on the musculoskeletal system is in any given situation. For example, it is possible to calculate how much strain is on the discs in the lumbar region if a person is standing with a straight back tilted forwards 45 degrees.

To do the math, there are some values ​​we need to know first:

  • Height and weight of the person performing the transfer
  • How many degrees the person is bending forwards during the transfer
  • How much the patient being transferred weighs
  • And how far the reaching distance is

Is doing a calculation like this unrealistic in a busy working environment? Absolutely! So, let me just provide you with an example.

Most who work within care have at some point needed to lift a patient's legs, e.g. for examination purposes or when the patient needs help getting their legs into bed.

Using this case as an example, we might have a situation with a caregiver who weighs 80 kilos, is 186 cm tall, and bend 45 degrees forward, lifting a patient's legs, weighing 10 kilos, at a reaching distance of 30 cm. 

This case will result in a strain on the caregiver corresponding to approx. 255 kg on the disc in the lumbar region (or the weight of an adult male lion). If we further take into account, that the caregiver is often not just standing still, but is lifting and moving the patient's legs, the load must be multiplied by 3, and the adult male lion turns into a large rhino equivalent to 765 kilos!

How is this Useful to Me (you might ask)?

I do not deceive myself with thinking that you are going to do biomechanical calculations before you help a patient (I can only dream), BUT, I do imagine that you, by being aware of how strenuous an ordinary patient transfer is, already is well on your way to making knowledge-based decisions about moving and handling.

The main point I want to make here is that you should not blindly perform patient transfers without first evaluating the situation to make sure, that you are not putting yourself at risk of a work injury.

Make sure you have the proper assistive aids, and do not make do with whatever you have at hand (such as towels or linens). And if you are experiencing back pain or aching shoulders after having transferred or repositioned a patient, you should think about getting an assistive living device such at the VENDLET system for the given patient or resident.