By Dr. Carl C. Howard III and Dr. Carl C. Howard Jr.
Have you ever wondered just what forces are exerted on the back while using Steadicam? This study was done to find that answer.
A dynamic Surface Electro Myograph (SEMG) was used to measure the increase in muscle activity while an operator was wearing a 70 lb Steadicam body-rig.
Electrodes on Glenn DiVincenzo, SOC register muscle activity during movement. He turns as tough moving a Steadicam to the side, while Dr. Carl C. Howard III uses the computer to record the result.
Measurements were taken on the muscles of the neck and low back during 5 different common motions of the steadicam operator. The measurements were taken first without vest and Steadicam apparatus, and then while wearing the vest and Steadicam apparatus. The 5 motions were:
1.Standing, moving the camera forward;
2.Standing, moving the camera to the side;
3.Standing, moving the camera to the back;
4.Standing, going to a lunging position;
5.Standing, going to a seated position.
The study was performed on three people. Glenn DiVincenzo, SOC (Subject 1), a 6.1“ 185 lb male, Liz Ziegler, SOC (Subject 2) 140 lb female. Both of these people were experienced Steadicam operators. And Carl Howard, DC (Subject 3), a 6.1“ 210 lb male, who had never seen a Steadicam before, let alone operated one.
Methods
The basic principle of the SEMG is simple. When a muscle contracts it gives off electricity which can be measured in micro-volts (1/1,000,000 of a volt). The more a muscle has to work the more electricity it gives off. For this study, measurements were taken along the posterior muscles of the neck along with the posterior muscles of the low back. Measurements were first taken in the 5 motions without the Steadicam apparatus and then with the Steadicam apparatus on. For each motion the two figures were compared and a percent difference was obtained. The results were quite interesting.
Figure 1 – This graph shows the muscle activity during one such test. Markers 1, 3, 5 show the camera at arm’s length. Markers 2, 4, 6 show the camera close to the body.
Results
It must be noted that this study was performed on only three people and therefore should not be taken as scientific fact but as a basis from which to build our knowledge and better understand the usage of this equipment in a safe and effective manner.
The results of this study are best understood if we examine each position individually. The percent differences are WITHOUT the Steadicam apparatus vs. WITH the Steadicam apparatus.
What do all these numbers mean?
The main information these numbers reveal is that the muscle activity of the three subjects tested increased an average of 108% in the neck and 158% in the low back over the five tests. Certain individual tests revealed increases that were significantly higher than others. For example, in position 3 (Standing, moving the camera to the back) while there was only an average of 49% increase in muscle activity in the neck, there was an average of 278% increase in muscle activity in the low back. From what this author understand, this motion is used the least of the 5 motions studied, and for good reason. The large increase in muscle activity combined with the twisting motion necessary for this motion can be dangerous, significantly increasing the possibility of a low back injury.
Gender difference
Another interesting finding was that the female of the subject group used the muscles in her low back 3 times more than the muscles in her neck, whereas the men used two muscle groups virtually the same amount. I postulate that these results were obtained because females are proportionally stronger in the lower half of their bodies, and males are more proportionally equal from upper body to lower body.
Steadicam effects
To examine the effects of the motion of the Steadicam on the body we must look at graph 1. Graph 1 is taken of subject 3 during position 1, on his low back, (Standing, moving the camera forward). Lines 1, 3 & 5 represent the camera at arm’s length, where lines 2, 4 & 6 represent the camera close to body. With the camera being on the right side, you can see that with the camera at arm’s length ( the top of the graph) the muscles on the right side of the low back are averaging around 900 micro-volts, whereas at the bottom of the graph, with the camera close to body , the muscles are averaging 90 micro-volts. This means that the camera at arm’s length puts 10 times the amount of stress on the muscles of the low back than when the camera is at the side of the body. So let’s put this into real numbers. Assuming the entire camera apparatus weighs approximately 70 lbs, and the average width of a person’s torso is 9 inches. When the camera is 9 inches in front of the body, you are putting 70 lbs of force on the low back. When the arm is fully extended and the camera is approximately 27 inches in front of the body, you are putting 210 lbs of force on the low back. (See figure 2). This is quite a substantial force and explains the ten fold increase in muscle activity with the camera at arm’s length.
Standing, going to a lunging position.
Conclusion
The question remains, what can be done to use the Steadicam more safely? I have four main recommendations for those who will be using the Steadicam.
1.Proper posture – Proper posture in this case means keeping your legs under your weight at all times and avoid bending at the waist as much as possible. If it is required of you to put yourself in an awkward position with the Steadicam, have spotters standing close by to help you with any difficult movements.
2.Keep the camera as close to your body as possible – As shown in the figures and diagrams, the closer to your body you keep the camera to less stress you put on your back and the less chance you have of injuring your back. When those times arrive when you must hold the camera at arm’s length, only do it for short periods of time and use a support if possible.
3.Try to avoid standing and turning the camera to the back – The combination of the twisting involved and the stress put on the low back greatly increase the possibility of a low back injury, particularly a discal injury.
4.Maintain a good exercise program – Although no exercise program will guarantee freedom from a back injury, a good exercise program can greatly decrease the possibility of a back injury.
HOW?
I have four main recommendations to keeping a strong and healthy back:
1.Strengthen the muscles of the low back
2.Strengthen the abdominal muscles
3.Strengthen the leg muscles including glutes, quadriceps, hamstrings and calves.
4.Regularly stretch the hamstrings and low back
Proper exercises and stretching even for people already in great shape will undoubtedly make operating a steadicam much safer.
Liz Ziegler moves the camera from a standing position to the back
Stay safe
When filming with a Steadicam or any other type of camera for that matter always be aware of the safety measures involved. Taking the few moments to think of a safer way to accomplish a shot may save you immeasurable amounts of time, money and pain. 80% of all people will experience low back pain at some point in their lives. Don’t push the odds higher by not following good safety procedures and good common sense.
Acknowledgements
The authors would like to thank all those who gave their time and effort to make this project possible and successful: Bill Hines, Liz Ziegier, Glenn DiVincenzo, Ray Stella and David Robman, all active SOC members.
Dr. Carl C. Howard III – after he completed his undergraduate studies at the University of California at Irvine in biology, he graduated from Los Angeles College of Chiropractic. He is currently in private practice in North Hollywood, CA.
Dr. Carl C. Howard Jr. – Recieved his BS in Microbiology from Lewis and clark College in Portland, Oregon and his doctorate of Chiropractic from the Los Angeles College of Chiropractic. He has been in private practice in North hollywood, CA for 32 years.
