When Should I Replace My Shoes?

Frequently asked questions by our customers are: How do I know when my shoes are worn out and how long will my shoes last? These are difficult questions for us to answer. Few customers can give us an accurate account of how much they use their shoes. As well, we know that a shoe will be broken down long before it looks worn out. If we could provide a test for wear and tear on athletic shoes or a mechanism whereby we could monitor the usage of shoes we would most certainly sell more shoes. Without these tools we can only advise as follows:

If you have 300 to 500 miles of walking or running on your shoes you will have worn out most of the shock absorption and arch support.

If you want to assess the wear on your shoes look for the following signs of fatigue:

The Whys and Hows of Hill Running

Why do hills?

Endurance Muscular Strength

"Hills provide resistance to the main running groups, primarily the calf muscles and quadriceps." This in turn allows the runner to spring forward with greater mechanical energy . I believe one of the limiting factor in the speed with which any runner can move forward is leg strength. There could be some relationship between the overwhelming success of the Kenyans and Ethiopians and their familiarity with hill training.

Economy of Movement

"Your running economy determines how fast you can run using a given amount of oxygen. Elite marathoners may range in Max VO2 from 69 to 90ml/kg O2 but their race performances will not necessarily correlate. This is due in part to the effect of different running economies. "Hill training strengthens as it coordinates the dynamic action of running and can bestow all the running power you need." The specificity of training rule also comes into effect here in that only hill training will properly prepare you for racing a hilly route.

Increasing Aerobic Capacity

I think of hill training as a controlled but effective form of speed training which should stress the cardiovascular system at about the 75% to 85% Max Heart Rate. The hill workouts should provide a workout similar to the effects of a tempo run which is why we choose to do long hills as opposed to short steep ones.

How to do Hills.

Tempo Pace Running

To me the heavy hitters in training for distance running are:

The Long Run

Overall Weekly Volume
Tempo Running

What’s in it for me? Why do Tempo Pace Running?
The most effective way to improve your lactate threshold is to run at your current lactate threshold or a few seconds faster for a continuous run of 20 minutes or more (or at that pace broken into intervals of 5 minutes with 1 to 2 minute rests).  Lactate threshold is the pace where your body starts to produce lactic acid which is a byproduct of burning carbohydrates (glycogen) anaerobically.

What’s the big deal with Lactate Threshold?
A high lactate threshold is the most important physiological variable for endurance athletes.  Lactate threshold most directly determines your performance limit in any event lasting more than 30 minutes.
The average runner’s lactate threshold occurs between 75 to 85 % of his or her maximum oxygen capacity (VO2 max).  The faster distance runners will have a higher lactate threshold and therefore can maintain a higher intensity without building up too much lactate in their blood.  Too much lactate in the blood will slow you down because at a certain level it becomes toxic.

How do I know I’m Running at Tempo Pace?

Why not go faster than the Tempo pace?
The rule of specificity of training comes into play here.  If you run faster than the proper Tempo pace you may be able to maintain the pace for 20 minutes but it will not have the effect of raising your lactate threshold. You will most likely be running at interval pace which is training a different part of your aerobic system.

The role of carbohydrate in exercise and performance - by Doug Cook

It seems we’ve done a 180 degree turn. A century ago beef was considered the most important food for an athlete’s diet because of its high protein content. Today carbohydrate is recognized as ‘nutrient supreme’ both for endurance athletes and power/strength athletes.
Carbohydrate is the primary fuel for working muscle whether that’s during a long distance run or during a series of high-power repetitions in weight lifting. It’s true that fat serves as a fuel source as well, but carbohydrate is required in order for fat to burn completely with the help of oxygen. Having adequate carbohydrate is what determines how long a person can exercise. Even during moderate levels of activity (less than 60% maximum heart rate) when more fat is being used as fuel, adequate carbohydrate is required to maintain this energy producing system – carbohydrate stores will run out long before our fat stores.
Carbohydrate is so important for athletic performance that the International Olympic Committee (IOC) has a position statement which states ‘athletes should aim to achieve carbohydrate intakes that meet the fuel requirements of their training programs and also adequately replace their carbohydrate stores during recovery between training sessions and competition’.

Carbohydrate before exercise

The role of carbohydrates before exercise is to ensure that glycogen stores (the storage form of muscle and liver carbohydrate) are maximized. By having adequate glycogen stores, an athlete can get the most out of their training by ensuring that their muscles have a steady supply of quick and useable fuel.
Carbohydrate should be the foundation of an athlete’s diet. Sources include whole grain cereals and breads, legumes (kidney beans etc), fruit, starchy vegetables and low-fat dairy. Carbohydrates should be eaten at every meal and snack.
The amount of carbohydrate required depends on many factors including both the type and intensity of activity, duration, frequency and the size of the athlete. For those engaged in 1 to 2 hours of moderate to intense activity per day, carbohydrate requirements are 6-8g/kg body weight, greater than 2 hours per day would require 8-10g/kg body weight. The muscle’s ability to store carbohydrates increases greatly with training.

Carbohydrate during exercise

During exercise, carbohydrate serves to prevent low blood sugar (bonking) and provides extra fuel in ‘real time’. Glycogen is being used by muscles but stores are limited, but by consuming carbohydrate during exercise, an athlete can enhance performance by helping to delay glycogen depletion. As a general rule, 30-60g/hr of carbohydrate should be consumed.

Carbohydrate after exercise

Carbohydrate consumption after exercise allows for replacement of glycogen stores in the same way carbohydrate does when consumed as part of a daily diet. The difference is that immediately after exercise, the muscles are primed to absorb many times more carbohydrate compared to the time interval between training sessions. There is a two hour window after exercise when glycogen synthesis is maximized with the first 30 minutes being most critical. The rate of glycogen synthesis is 45% lower after the two windows which makes the timing of carbohydrate consumption paramount. Try to consume 1g carbohydrate/kg of body weight within 30 minutes after training. Having some protein with a post-exercise meal/snack (up to 15g) will not hamper glycogen synthesis and will deliver amino acids into the muscles for repair.
The symptoms of gradual glycogen depletion related to successive days of heavy training can be subtle. These symptoms can increase over a week’s time or longer, producing feelings of sluggishness or heaviness in your muscles which will hinder training efforts, and negatively affect performance. Adequate carbohydrate consumption will alleviate this. Carbohydrates should be the foundation of an optimal diet for both endurance and strength athletes.
Doug Cook, RD MHSc CDE is a clinical dietitian and certified diabetes educator working at St Michael’s Hospital in Toronto. Doug at dc_dietitian@hotmail.com or visit his website www.wellnessnutrition.ca