It’s that time of year again……..back to school shopping! While most parents and students are focused on getting all the necessary items for the year, the backpack itself is often overlooked. Backpacks have important health impacts on children, whose bodies are still growing and developing. Sometimes parents try to get big backpacks that will be able to fit all the books, pencils and electronic devices needed, but a heavy or poorly fitted backpack can affect a child’s current and future musculoskeletal health. Often children are forced to hunch over under the weight of heavy backpacks, or shift their weight to one side, and this puts them in a prolonged position of flexion. Over time creep causes the ligaments to lax, the joints to move out of place, and the muscles to get over fatigued and strained. This affects both the posture and gait of a child causing imbalances, which can be a factor in future injuries.
Here are a few tips to keep in mind when you are choosing and packing a backpack:
1. Find a backpack that fits your child’s body and is adjustable as they grow
2. When packing the backpack, it should be between 10-15% of the child’s body weight.
3. Make sure that the weight is evenly distributed in the backpack, so the child doesn’t end up using one side of the body’s muscles more than the other. Backpacks with many compartments are helpful in trying to accomplish this.
4. It is important that your child wears both straps. Having the strap over just one shoulder can cause them to lean to the one side, which over time could cause the spine to curve.
5. The shoulder straps should be adjusted so that the backpack fits closely to the upper part of their body. If the backpack is further away from the body it throws off your child’s balance, and will bounce from side to side causing their muscles to work harder to stabilize. The backpack should never hang more than four inches below the waistline.
Dr. Natasha Speedie
B.Sc.(Hons.), D.C., A.R.T., C.M.A.G.
Chiropractor, Active Release Technique Practitioner
Clinical Acupuncture Provider
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Source: Canadian Chiropractic Association
Stretching Part 1: Are you really lengthening muscle?
By Henry Candelaria, BPHE, DC
For years, stretching has been promoted as an integral part of any exercise program because of a reported decrease in risk of injury by improving range of motion (ROM), reduction in pain, reducing stiffness, and increasing overall athletic performance. Many different stretching techniques exist and therefore many different recommendations also exist, some based on scientific literature and others based on traditional strength and conditioning practices. However, new research has challenged these long-held concepts about common stretching programs and it is the hope of these series of articles to clarify some of those concepts and clear up the misconceptions through highlighting some of the new recommendations.
In this first segment, we will reveal what is actually happening during a stretch and how stretching appears to be increasing extensibility of muscle. In the second segment, we will talk about the role that stretching has to play, if any, in reducing the risk of injury and improving athletic performance. In the final segment of this three part series, we will summarize the current literature on the best stretching techniques to use, when to use them, and how frequent stretching is to be performed.
Let’s begin by talking about what happens during a stretch. There is a vast amount of evidence to support that stretching will improve ROM of a joint by allowing the muscles that cross that joint to be more extensible. If you think of a thick elastic band that undergoes repetitive stretching or a prolonged stretch, the elastic band will become less resistant to stretch over time due to the heating effect that occurs to the band with repetitive motion. The theory behind stretching is similar, except instead of elastic bands, we are dealing with living muscle tissue. There is a special property of living tissue that is referred to as viscoelasticity. What this means is that upon holding living tissue under tension for a prolonged period of time, the force required to hold that tissue at that length is reduced over time. This implies that a tissue can therefore withstand more tensile force at a specific length without undergoing damaging changes to the structure of that tissue. So, what this means is that a muscle tissue that is stretched is theoretically able to produce more force at a specific length without causing injury. This has obvious implications for performance. If an athlete is able to produce more force at a greater ROM without undergoing injury, then theoretically they are likely to have greater success than their counterpart who is limited in force production at extremes of ROM. This will be discussed further in the follow-up installments in this three part series.
However, this is not the whole picture. Recent evidence has suggested a neural based reason for the apparent increase in ROM that is seen with stretching. How does the nervous system influence ROM and what is the difference between objective and apparent increases in ROM? Well, all of us have experienced that uncomfortable sensation that is associated with stretching which feels like a numbing pull on muscles. It is not really painful but it is not comfortable either. That sensation is the key to improving apparent ROM. Before we continue, let me define what I mean by apparent and objective ROM. Apparent ROM implies that the joint appears to be traveling through a greater ROM because of nervous system factors, when in fact there is no change in length of the muscle if measured histologically. Objective ROM is when there are histological increases in ROM meaning that the muscle tissue itself has actually become longer. The majority of ROM increase that is experienced during stretching is achieved through apparent increases in ROM. That is that the increase in ROM that is seen with stretching is a function of an analgesic effect that occurs during the stretch. In other words, it hurts less to stretch!! We actually become numb, in a sense, to that uncomfortable sensation associated with stretching, and therefore over time and with repetition, we can take our joints to extremes of ROM.
It is important to note that this effect is subtle and does not mean that if held and pulled to an extreme ROM, a muscle will increase extensibility without causing damage to that muscle or an associated joint! Taking a joint to extreme ranges is always dangerous and should be done under the supervision of a qualified professional, if done at all! Stretching as normal however, has many other proposed benefits that will be discussed in the upcoming monthly newsletters, so please look out for these along with other of my monthly installments on musculoskeletal health.
If you have any questions related to this article, or any musculoskeletal related questions, feel free to contact me at firstname.lastname@example.org.
Dr. Henry Candelaria