I'd like to say that I was surprised when I joined my latest field crew and saw that 3 out of 4 of my colleagues were wearing wrist supports and complaining about pain in their wrists and hands (the 4th has a history of actively participating in physiotherapy for previous damage) - but working in the field with a repetitive strain injury (RSI) seems to have been relegated to the significance level of stiff muscles, an expected annoyance that simply needs to be ignored in order to go about our daily activities. While the irritation of a stiff muscle may be temporary, however, the damage caused by an RSI can be long lasting and debilitating. The bad news is that the repetitive motions themselves may be unavoidable during an excavation - the good news is that there are simple steps which can help prevent these motions from causing an RSI, and with a little awareness and caution, we can further decrease our risk.

 RSIs - also known as Cumulative Trauma Disoders (CTD), Occupational Overuse Syndromes (OOS), Repetitive Motion Syndromes (RMS), and others - can be caused by restricted blood flow. When a muscle is tensed, bloodflow through the capilliaries is restricted. A continuously tensed muscle cannot be supplied with enough oxygenated blood (which can cause cell damage and pain), and the body will attempt to compensate by employing supportive muscles to carry out the required function. The supportive muscles, however, are less effective at the task and will break down even more quickly under continual stress. These tensed muscles may put pressure on nerves and cause tingling or numbness, and the lack of oxygenated blood can cause inflammation and slow the healing process - so that even when rest is allowed and the symptoms decrease or disappear temporarily, it will take less stress to cause them to appear the next time (http://www.tactuskeyboard.com/kp_ctd.htm).

One of the most common RSIs is the infamous Carpal Tunnel Syndrome, which effects the wrist and hand, and can cause pain all the way up the arm. It is caused when the median nerve, which is the nerve running from one's forearm into the hand, becomes pressed at the wrist due to inflammation of the nerve sheath caused by improper lubrication (a result of continual use). Symptoms typically appear slowly and gradually, often manifesting as a tingling sensation or numbness. Symptoms often appear during the night or upon first waking in the morning. Moderate symptoms can include a tingling sensation during the day, and with severe untreated cases the subject may not be able to grasp small objects or identify temperature by touch (http://www.ninds.nih.gov/disorders/carpal_tunnel/detail_carpal_tunnel.htm).

(Image from: chiropractic-help.com)

Although there are several ways for a trained physician to diagnose Carpal Tunnel Syndrome, there is also a simple self-diagnostic test called the Phalen Maneuver (after it's creator, George S. Phalen) which can be performed at any time. With your forearms parallel to the ground and at shoulder height, press the backs of your hands together with gentle but firm pressure. If within a minute any of the Carpal Tunnel Syndrome symptoms become present (including burning, tingling, or numb sensations in the fingers), you may be at risk and should consult a physician. Do not hold the Phalen Maneuver for longer than the required minute for the test, and stop immediately if symptoms begin (http://www.thehelpinghand.com/rsi/rsi.htm).

There are treatments available for Carpal Tunnel Syndrome and other RSIs, and while there is no substitute for the advice of a trained physician or physiotherapist, there are numerous online resources available that recommend specific stretches as an injury prevention tool. Try to become aware of any repetitive activities you undertake in a typical day which may be altered to reduce risk, and remember to stretch at the beginning and end of each day in the field. The following simple stretches can help get you started:

(Image from: clarinet.org)

References:

http://www.tactuskeyboard.com/kp_ctd.htm

http://www.ninds.nih.gov/disorders/carpal_tunnel/detail_carpal_tunnel.htm

http://www.chiropractic-help.com/carpal-tunnel-syndrome.html

http://www.thehelpinghand.com/rsi/rsi.htm

http://www.clarinet.org/clarinetfestarchive.asp?archive=50

Other useful websites:

http://cupe.ca/rsi/repetitive-strain-injuries