The Blade Runner

ImageIn light of the recent spotlight on Oscar Pistorious, a double amputee who competed in the 400m race of the London Olympics, I would like to revisit the debate of whether the “high tech” carbon fibre prosthetic legs which Pistorious competes in offers an unfair advantage. 

As usual, I would like to being your attention to a research study published in the Journal of Applied Physiology. This one was done back in 2009 but I believe that it is still relevant. The authors conclude that: “…running on modern, lower-limb sprinting prostheses appears to be physiologically similar but mechanically different from running with intact limbs.”

What does this mean?

In terms of metabolic consumption, the authors claim that with the prostheses, energy cost was up to 17% lower compared to able bodied elite 400m runners. Therefore, I am not sure why the authors state that running on modern sprinting prostheses vs able legs are metabolically similar. To me, a 17% reduction in energy cost over the time course of 400m could be quite a significant advantage. 

In terms of mechanical differences, the study showed that the vertical ground reaction force that can be generated in lower with the prostheses. However, the lightness of the prostheses compared to intact limbs allows the legs to repositioned up to 15.7% faster. Whether this tradeoff amounts to an unfair tradeoff is yet to be determined.

To summarize, the research is not black and white. However, in my opinion, I do think that the prostheses offer an advantage. It is just logistically difficult to conduct comparative studies between able bodied and disabled athletes. But even if Pistorious does gain an unfair advantage, his story should be an inspiration to all. I salute him.

Exercise-oncology

Exercise therapy for individuals undergoing treatment for cancer may help counter the adverse side-effects. Many of the drugs which are used to fight cancer are also cardiotoxic, meaning they damage the heart. Some medications also lead to a loss of muscle mass.

Exercise interventions can help counter these limitations to the cardiovascular and musculoskeletal systems. Recent work from the Duke Cancer Institute can be found here.

Evidence based exercise prescriptions for cancer, based on the work of Lee Jones, Duke Univeristy:

3-5 days/ week at 60-75% HRR, 20-45 min per day

 

Barefoot vs shod running

I’ve had many inquiries about barefoot running and to be honest, I’m not too familiar with the literature on this topic. However, I was recently at a conference, where an expert consensus panel basically hashed out what we currently know about barefoot running. So for those of you interested, here’s the run down :

Claim 1: Barefoot running is associated with toe landing while shod running with heel landing- This claim is not correct. Kinematic (think experiments with high speed cameras) have shown that landing pattern is subject specific, and has very little to do with footwear.

Claim 2: Forces during barefoot landing are smaller than during shod running, therefore reducing injury potential- this claim is not entirely true. It is true that the external forces (force between the foot and the ground) has a smaller peak in barefoot running, but in the context of injury, the forces that are relevant are internal (the force across joints etc.) not external. It is incredibly difficult to study these internal forces, but through estimations, researchers have shown that there is not much of a differences especially around the ankle joint. Forces tend to remain the same but shifted towards other muscles. The implications of this still need to be substantiated.

Claim 3: barefoot running is associated with fewer injuries. there is currently NO study that has shown conclusively that this is the case.

Claim 4: barefoot running provides more training (compared to shod running) for the muscles that cross the ankle joint. Studies have actually shown that shod running can lead to higher activation of these ankle muscles compared to barefoot running.

Here’s a summary from the conference for anyone interested.

 

“Toning” shoes: update

For those of you who read my original post on toning shoes, here’s an update. Sketchers, the maker of the “shape-ups” line of toning shoes is being fined $40m by the FTC.

Here’s the story on CNN.

 

Sedentary behaviour guidelines

With the rising rates of obesity, we all know the importance of physical activity. But encouraging physical activity is not always easy. Please see these newly developed guidelines on how to counter sedentary behaviour. These guidelines were made by the Canadian Society for Exercise Physiology (CSEP).

0-4 years

5-11 years

12-17 years

“Toning” shoes

I’m sure you’ve seen them around. Shoes that claim to shave extra calories just by wearing them. Many of these shoes are designed with a “rocker” or unstable sole that supposedly increases muscle activation, leading to more calorie spent. Many manufacturers have hopped on this wagon (including: Sketchers “shape-ups”, reebok, MBT, etc.). But do these shoes really help tone your body?  Lets first take a look at the 2 major claims:

  1. Toning shoes lead to higher activation of muscles in the lower leg, buttocks, and thigh
  2. Toning shoes lead to a greater caloric expenditure

So lets look at the research. On a side note, here’s a classic example of how you have to be careful when interpreting studies. Many of the clinical studies that support the benefits of these shoes tend to be funded by the manufacturers themselves. Sometimes it takes a bit of digging to find this out, but trust me, all information can be found if you look hard enough.

Here’s a study that I’m sure was independently conducted. The researchers compared toning shoes (various brands) to normal New Balance runners with respect to physiological variables such as energy expenditure. They also used a technique called electromyography (EMG) to actually measure the muscle activity while the shoes were worn.

Long story short, they found no differences between the toning shoes and the regular runners in terms of energy expenditure OR muscle activity!

So despite the commercials featuring well-toned celebrities, please be aware. Sometimes shortcuts are too good to be true.

New spinal-cord injury exercise recommendations

New evidence based exercise recommendations for individuals with Spinal Cord Injury. The original article can be found here.

Pesticide load: best and worst foods

 

Study: Long term exercise in persons with SCI

Secondary complications related to inactivity are highly prevalent in spinal cord individuals. This long term study shows that exercise can result in improved quality of life and both improvements in physical and psychological function.

The free article can be downloaded from Nature.

The study basically showed that a 9 month exercise program (2 times per week, strength and arm ergometer training) can increase fitness and psychological well being. Participates report less pain, stress, and depression after exercise training. Perceived and overall quality of life also increased.

Here’s the exercise intervention:

2x/week

arm ergometry for 15-30min, 70% max. heart rate.

Resistance training circuit with pulley machines, and free weights. 2 sets per exercise, 50% 1 rep max to start. Progress to 3 sets after a month. Resistance loads were  increased every 6 weeks.

Exercises were chosen for: forearm/wrist, biceps, back, chest, abdominals, shoulder, triceps, and legs (applicable to some subjects only).

Wheelchair users: how to preserve your shoulder function

There are certain strategies that wheelchair users can employ to lower the risk of shoulder pathologies. Most of these strategies are fairly straight forward and feasible.

1. make sure your wheelchair is configured properly. An occupational therapist could check this for you. A properly set up chair will decrease the forces and strain require to propel your wheelchair. Adjust the rear axle as far forward as possible without making the wheelchair too unstable. This will allow you to use more of the wheel without having to reach way behind you to grab the rim.

2. try to get the lightest wheelchair possible, with tires with the lowest rolling resistance. This will make a huge difference when propelling up slopes.

3. learn the proper stroke! use long strokes rather than small frequent ones. Allow your arms to recover naturally after a forward stroke. Don’t jerk the arms back.

4. During transfers, vary the arm you lead with to distribute the load.

5. Flexibility and resistance exercises! These should target the shoulder girdle (rotator cuff, pectorals, etc.)

More information here.