This article was
written by ErgoRisk

Strong Knees 1: Basic Structure

• Guess which joint is the largest in the human body?

• Guess which bone is the longest bone in the body?

• One of the reasons our knee joint needs to be so big is that it bears very high forces from the longest bone (and lever) in the human body (the upper leg bone). Since we are dealing with such a large joint and forces, it shouldn’t be a surprise that knee problems are one of the most common injuries in the workplace.

• The knee joint appears pretty simple and breaks down into two important joints: The knee cap joint ((#1) between the underside of the kneecap and the bottom of the upper leg bone) and the knee joint ((#2) between the long bones of the leg).

• The knee joint itself is a balancing act of muscles, ligaments and cartilage. Similar to the back and shoulder, if the joint gets slightly out of balance or one of the pieces of the puzzle are strained, the impact to our daily lives can be severe.

This article was
written by ErgoRisk

Strong Knees 2: How the Knee Gets Injured

• If you look at the injuries at your worksite, you will probably find that knee injuries are one of the top 3 body areas injured each year.

• When you dig a little deeper, you may find that many of the reports of injury come from similar causes.

• Knee strains frequently occur when we lose control or balance when performing common tasks. Have you ever lost control as you were climbing stairs or off of motorized equipment? Slipping while climbing is an easy way to injure your knee or your back. When someone slips, this can put their knee into an awkward position, and the knee ligaments (hold the knee bones together) can become strained. If you ever watch soccer or NFL football, you are probably familiar with players that strain their knee when they lose control of their footing and land awkwardly. If you look in the picture, you will notice the worker using three points of contact as he descends the locomotive stairs. Three points of contact guarantees stability and reduces your risk of injury.

• Knee discomfort and injuries can also develop over time from poor knee alignment. If our leg muscles don’t hold our kneecap in the proper position, the underside of the knee can get irritated and painful. One interesting fact is that when we work in a deep crouch, the pressure between the back of our kneecap and our leg bones can be up to 7-8 times our bodyweight! Even climbing stairs results in pressures of 3-4 times our bodyweight. http://www.clinicalsportsmedicine.com/chapters/24b.htm

• Be on the lookout for the common factors for knee injuries: awkward positions of the knee (e.g. crouching, kneeling, twisting the knee), static postures (e.g. being in one position for a long period of time), high forces (e.g jumping from one level to the next or squatting/kneeling causing high force behind the knee) and our body weight.

This article was
written by ErgoRisk

Strong Knee 3: Proper Knee Alignment

• Knee injuries and pain happen when one of the knee structures gets overloaded or if the knee is forced to work when not in good alignment.

• Imagine trying to stack building blocks on top of one another when one or more of them are on an angle. If you put a lot of force on top of the blocks, chances are that one or more of them will slip out of position or give way.

• Safe alignment for the knee is with the kneecap pointing in the same direction as the toes.

• The knee is strongest front to back, so avoid twisting or putting sideways stress on your knee as much as possible. It’s easy to ignore our knees in an effort to get the job done quickly, but an extra few seconds to set your foot down safely can be the difference between comfort and injury.

• Muscle imbalances in the hamstrings muscles behind the knee or quadriceps muscles in the front of the thigh can result in the knee cap being pulled out of position. So as always, strength and flexibility are critical to healthy knees.

This article was
written by ErgoRisk

Strong Knee 4: Knee Care at Work

• Knees are often one of the last things we think about when we are setting up a job. Commonly, we stress our knees when we rush or push to get the job done.

• Jumping down from equipment, kneeling when working at floor level, working in a crouched position for long periods time – all of these are examples of stressful events to the knee that can usually be eliminated with an extra 5 seconds on the job or 5 minutes when prepping your job.

• To keep your knees healthy for years to come, try to think of the following tips as you set up your work today:

1. Look for ways to raise work off of floor level to avoid awkward knee postures
2. Alternate sides if you must kneel
3. If you have to work at floor level – use knee pads, kneeling pads or at least a couple of pieces of cardboard
4. Support yourself on nearby equipment when standing up from squatting or kneeling
5. Always try to maintain three points of contact when climbing stairs or on/off equipment
6. Replace your boots (or just the soles) if you notice a lot of wear
7. If you want to understand the impact of a knee injury, take the time to talk to someone who has suffered. It may be all the motivation you         need.