Running Shoes

Here's a great article featured on http://www.acatoday.org/

How to Select Athletic Shoes

Too many people choose fashion over function when purchasing athletic shoes, not realizing that poor-fitting shoes can lead to pain throughout the body. Because footwear plays such an important role in the function of bones and joints—especially for runners and other athletes—choosing the right shoe can help prevent pain in your back, hips, knees, and feet.
Unfortunately, there is no such thing as the very best athletic shoe—every pair of feet is different, every shoe has different features, and overall comfort is a very personal decision. For this reason, it is recommended that you first determine your foot type: normal, flat, or high-arched.

The Normal Foot:
Normal feet have a normal-sized arch and will leave a wet footprint that has a flare, but shows the forefoot and heel connected by a broad band. A normal foot lands on the outside of the heel and rolls slightly inward to absorb shock.

Best shoes: Stability shoes with a slightly curved shape.

The Flat Foot:
This type of foot has a low arch and leaves a print that looks like the whole sole of the foot. It usually indicates an over-pronated foot—one that strikes on the outside of the heel and rolls excessively inward (pronates). Over time, this can cause overuse injuries.

Best shoes: Motion-control shoes or high-stability shoes with firm midsoles. These shoes should be fairly resistant to twisting or bending. Stay away from highly cushioned, highly curved shoes, which lack stability features.

The High-Arched Foot:
The high-arched foot leaves a print showing a very narrow band—or no band at all—between the forefoot and the heel. A curved, highly arched foot is generally supinated or under-pronated. Because the foot doesn’t pronate enough, usually it’s not an effective shock absorber.

Best shoes: Cushioned shoes with plenty of flexibility to encourage foot motion. Stay away from motion-control or stability shoes, which reduce foot mobility.

When determining your foot type, consult with your doctor of chiropractic. He or she can help determine your specific foot type, assess your gait, and then suggest the best shoe match.

Shoe Purchasing Tips
Consider the following tips before you purchase your next pair of athletic shoes:

• Match the shoe to the activity. Select a shoe specific for the sport in which you will participate. Running shoes are primarily made to absorb shock as the heel strikes the ground. In contrast, tennis shoes provide more side-to-side stability. Walking shoes allow the foot to roll and push off naturally during walking, and they usually have a fairly rigid arch, a well-cushioned sole, and a stiff heel support for stability.

• If possible, shop at a specialty store. It’s best to shop at a store that specializes in athletic shoes. Employees at these stores are often trained to recommend a shoe that best matches your foot type (shown above) and stride pattern.

• Shop late in the day. If possible, shop for shoes at the end of the day or after a workout when your feet are generally at their largest. Wear the type of socks you usually wear during exercise, and if you use orthotic devices for postural support, make sure you wear them when trying on shoes.

• Have your feet measured every time. It’s important to have the length and width of both feet measured every time you shop for shoes, since foot size often changes with age and most people have 1 foot that is larger than the other. Also, many podiatrists suggest that you measure your foot while standing in a weight bearing position because the foot elongates and flattens when you stand, affecting the measurement and the fit of the shoe.

• Make sure the shoe fits correctly. Choose shoes for their fit, not by the size you’ve worn in the past. The shoe should fit with an index finger’s width between the end of the shoe and the longest toe. The toe box should have adequate room and not feel tight. The heel of your foot should fit snugly against the back of the shoe without sliding up or down as you walk or run. If possible, keep the shoe on for 10 minutes to make sure it remains comfortable.

How Long Do Shoes Last?
Once you have purchased a pair of athletic shoes, don’t run them into the ground. While estimates vary as to when the best time to replace old shoes is, most experts agree that between 300 and 500 miles is optimal. In fact, most shoes should be replaced even before they begin to show signs of moderate wear. Once shoes show wear, especially in the cushioning layer called the midsole, they also begin to lose their shock absorption. Failure to replace worn shoes is a common cause of injuries like shin splints, heel spurs, and plantar fasciitis.

Glycine propionyl-L-carnitine increase in Exercise Performance

I wanted to post a note about this article a while back but did not have time. I found this very interesting in that it may help develop Peak power and at a minimuim should warrent a larger scale study. Any Questions Just ask.

"Glycine propionyl-L-carnitine produces enhanced anaerobic work capacity with reduced lactate accumulation in resistance trained males," Jacobs PL, Goldstein ER, et al, J Int Soc Sports Nutr, 2009; 6(1): 9. (Address: Patrick L. Jacobs, Department of Exercise Science and Health Promotion, Florida Atlantic University, Davie, FL, 33314, USA. E-mail: pjacobs4@fau.edu ).

Summary:
In a double-blind, placebo-controlled, crossover study involving 24 healthy male resistance trained subjects (average age: 25 years), supplementation with 4.5 grams glycine propionyl-L-carnitine (GPLC) 90 minutes prior to participating in an exercise testing protocol, was found to enhance peak power production and significantly reduce accumulation of blood lactate (16% less blood lactate production 14 minutes post-exercise), as compared to ingestion of a placebo. The authors state, "These findings indicate that short-term oral supplementation of GPLC can enhance peak power production in resistance trained males with significantly less LAC accumulation."

Testing: The assessment protocol consisted of five maximal effort 10-second cycle sprints performed with 1-minute active recovery periods between bouts. While Wingate type testing is typically performed using a single 30 second work period, repeated 10 second sprints have been used when testing exercise capacities similar to those required in relatively intense exercise. The sprints were performed using a Monarch 894E leg ergometer (Monarch, Varberb, Sweden) outfitted with pedal cages. The external resistance applied was equivalent to 7.5% of each subject's body mass. The testing protocol included a 10-minute warm-up period cycling on the test bike at a pace of 60 RPM, without external resistance. Following the warm-up period, subjects were directed to gradually increase the pace of their pedalling over several seconds until they reached a maximal pace of unloaded sprinting. At this point, with a verbal cadence, external resistance was applied thereby initiating a 10-second period of sprint testing and data collection. Verbal encouragement was provided by the investigators to continue sprinting at maximal pace throughout the 10-second bout. Subjects were directed to continue pedalling at a slower controlled pace during the 1-minute active recovery periods. With five seconds remaining in the recovery period, subjects were again directed to gradually increase their pedalling to a sprinting pace for the second sprint. This procedure was continued for a total of five 10-second sprint bouts.
Anaerobic power output of the sprints was determined using the SMI OptoSensor 2000 (Sports Medicine Industries, Inc., St. Cloud, Minn). Values of power output determined included peak power (PP) and mean power (MP) which in this case were the average values of power output during the first five seconds and total ten second period, respectively. The third power output measure was a value of power decrement (DEC) in which the difference in power output between the first and second five second periods are expressed as a percentage of the first.
Blood lactate levels were assessed using the Accutrend® Lactate analyzer (Sports Resource Group, Inc., Pleasantville, NY). The analyzer was calibrated using the standard control solutions prior to each testing session. Lactate values were determined at rest and post-exercise at minutes four and fourteen. Heart rate was measured using a Polar HR monitor system with values assessed at rest, during the final 5 seconds of each sprint as well as four and fourteen minutes following completion of the fifth sprint. Thigh girth was assessed using a Gulick tape with circumferential measurements taken 15 mm superior to the patella. Thigh girth was measured at rest and four minutes following completion of the final sprint interval.

Now I know the sample size was small but I think the methods are sound and the results are interesting and show a significant increase in anaerobic power.