Safety Matters

Back in February, my blog post focused on preventing slips. In this post, I am going to focus on trips, and no we aren’t talking about the fun, going on vacation, kind.

Both slips and trips can result in the same injuries:
• serious injuries due to a subsequent fall (broken bones, concussions, etc.)
• soft tissue injuries after the worker falls to the walking surface (rotator cuff, ligament damage)
• soft tissues injures as the worker catches themselves to prevent a fall

Even though slips and trips can both result in the same types of injuries, it is important to know that trip hazards are different than slip hazards, so we need to think about them differently and put into place different controls to prevent them.

Before continuing, I think it is important to restate that you won’t prevent slips and trips by just telling workers to pay more attention. It is true that inattention may be a contributing factor to a slip or trip, but since few of us pay attention to how we walk, we need to identify and control the actual hazards that can increase the likelihood that someone will slip or trip.

We can stop slip, trip and fall related injuries by identifying, assessing and controlling the hazards that cause people to slip, trip and fall.

Preventing Trips:
Why do we trip? In most cases we trip because our foot or lower leg hits something while we are walking or running. Anything that interferes with our normal gait pattern stops the normal forward movement of the foot or leg, causing us to lose our balance. When this happens we react by trying to stop a fall.  If there is a small to moderate loss of balance, we may be able to stop ourselves from falling by jerking back or throwing our lead food forward quickly. This forceful bodily reaction can result in strained or torn muscles in the back or lower body.

If the loss of balance is moderate to high then we are going to fall forward. Recent research¹ tells us that when we trip and fall, our brain knows we are about to fall before it happens. Unfortunately, the delay between the brain knowing and the muscles reacting is enough to make it impossible for us to stop the fall.

There is another way we can trip, and that happens when we step into a hole, or when a foot lands on an uneven surface, or when we move from one level to another and there is an unexpected change in elevation.  As above, the reason why we trip is because the normal movement of the foot is disrupted and we lose our balance.  I am sure you have had a stumble when you have been going up or down some stairs and suddenly find that the last step down, or up, is longer or shorter than you expected. Unfortunately, people tripping and falling on steps and stairs is all too common an occurrence.

Preventing trips on walking surfaces should be simple, because all we need to do is ensure they are free of anything that can obstruct the worker’s foot or lower leg, or interfere with normal walking patterns. Some things you can do to prevent trips are:
• Fill in any holes in walking surfaces and make sure that the patch is smooth and even, with no ridges or bumps
• Remove anything that does not belong on the walking surface (cords, debris, tools, etc.)
• Ensure that grates and mats sit flat on the walking surface, with no bumps, raised edges, etc.
• Make sure that there is nothing sticking up out of the walking surface, such as bolts, embedded stones, cut off posts, utility covers, etc.
• Fix or replace any tiles, bricks, boards or carpets that are damaged or uneven.
• Make sure that nothing sticks out into the walking path (lower cabinet drawers, pallets, unevenly stacked items, personal items in or around work areas, etc.)
• Remove doorway thresholds for all interior doors

Three other things are important to know about trip hazards. First, it doesn’t take much to trip you up. A ridge or bump that is only 6mm (1/4”) high can be a real ‘people tripper’, high enough to catch the bottom of your foot or your toe as it swings forward, but often too low to see.  So when looking for trip hazards, don’t ignore those small ridges and bumps.

Second, it is vitally important to ensure that steps and stairs are designed to minimize the risk of trips. This means making sure that all steps are the same height as the first step (going up or down). It is also important to make sure that treads are the same depth (min 11”) and that the tread’s overhang (nosing), if any, is no more than 30mm. Another important point to remember about stair design is visibility. People trip up or down because they can’t see the first step. Sometimes people walk right out into space because a short set of steps blend into the background so people can’t see they are coming to a change in the level of the walking surface.

Third, like slips, our expectations are also a key part of why trips do or do not happen. If we are walking on a trail in the woods, we expect there to be stones, roots, debris, uneven surfaces, etc. As such we take the time to look where we are going and where we are placing our feet. However, if we are walking inside, or on a person-made surface like a sidewalk, we expect these surfaces to be smooth and free of obstructions. Unless there are significant cues to tell us otherwise, we don’t expect, and therefore won’t see, many of the things that can cause us to trip and, potentially, fall.

In the workplace, it is important to identify the design and work process hazards that can lead to trip related injuries, and then do everything you can to eliminate them.

¹ Loss of balance during balance beam walking elicits a multifocal theta band electrocortical response. Sipp AR, Gwin JT, Makeig S, Ferris DP.  J Neurophysiol. 2013 Nov;110(9):2050-60