Holiday Fitness Challenge 2016


Friday, Nov. 4, 2016, to Sunday, Jan. 1, 2017

It is BACK by popular demand!  The XCELL Holiday Fitness Challenge!

This eight-week program is designed to help you prevent gaining unwanted weight that usually doesn’t go away after the holidays.

Plus, by staying active and motivated through friendly competition, you’ll better manage the stresses and craziness that goes along with this time of year!

“I started the [XCELL Holiday Fitness] Challenge to keep fit during the holidays…I didn’t win the Challenge overall but I still won because I didn’t gain any weight over the holidays!” – Nancy

”The competition was fun and had me doing things I NEVER would have typically done over the holidays like 5ks and lots of crunches”  -Vickie

Click here to view details and schedule.

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Running Injuries and How to Avoid Them

By John A. Mercer, Ph.D.
Biomechanics Laboratory, University of Nevada, Las Vegas

Runners get injured … anyone reading this part of the newsletter either knows this first hand or knows someone who has had a running injury. There is a wealth of research documenting the risk of injury to runner and can be summed up by considering this: If a 100 runners are followed during a marathon training program, as many as 75 will probably have some type of injury with about 20 of them having to stop running to let the injury heal.

Why is there such a high risk of injury during running? Each time your foot strikes the ground, there is an impact force of about 2-3 times your body weight. In a 30-minute run, a typical runner will have about 5000 impacts … it is the accumulation of all those impacts that are likely the root of the injury problem.

Unfortunately, no shoe design, or lack of wearing shoes, is going to solve the problem. The solution to avoiding running injuries is to avoid Too Much Change Too Soon. The body is amazing at adapting muscles and bone strength to stress like running. However, the body needs time to adapt … an injury is almost certain if too much stress is applied with too little time to adapt.

Any change in running distance, speed, surface, or shoes (new or change in model), for example, can be thought of as ‘change’ … too much of this change too soon can lead to an injury. The injury may not be immediate … which is why avoiding running injuries is so hard. Sometimes we do not realize how much stress we are placing on our bodies with a normal run … let alone a change in run in some way. Be sure to plan in your rest days and keep track of injuries … looking back on your training log you can sometimes figure out how much change in stress your body can handle.

What should a runner do when he/she is injured? This is a difficult question to answer because there are so many different types of running injuries … some of them you can continue to run with, some of them you will be better off not running and letting the body heal. Let’s say your injury is in that category … runners are notorious for going crazy if they can’t run! Here are some options: Elliptical trainer, Body weight support treadmill, and deep water running.

The Elliptical Trainer was designed to mimic the running motion while eliminating the impact with the ground. Overall, this does accomplish that … but the stride length is limited and the upper body motion is often restricted.

If you have $25,000, you can run on a Body Weight Support Treadmill. This type of treadmill ‘lifts’ the runner up to support some of the body weight. By doing that, the impact with the ground is less severe and some runners may still be able to train this way. The downside of this is that these treadmills are hard to find and are very expensive.

Another way to continue to run while injured is to run in the water. There is a good body of research that has demonstrated that runners can maintain their on-land running fitness and performance after using water running programs. There are two main categories of water locomotion: Shallow and Deep Water Running. During shallow water running, the feet are still in contact with the ground … it is a good idea to wear an old pair of shoes (or you can buy shoes specific for the pool). The downside of shallow water locomotion is that runners with certain types of injuries may not be able to place any weight on the feet.

Deep water running is down in the deep end of the pool where the runner cannot touch the bottom. Many runners will use some type of flotation device to help keep them upright so they can focus on maintaining a running motion (vs. treading water). There are several ways to ‘run’ in the water … it is a good idea to search YouTube for Deep Water Running (also known as AquaJogging). The two main styles are often described as ‘high-knee’ and ‘cross-country’. During high-knee style, your legs are moving up and down sort of like stair stepping … buy you are still trying to mimic a running motion. During cross-country, you are trying to reach forward a bit more with the leg … sort of like taking long strides. When using this style, you need to be careful that sometimes you can place too much stress on the back side of the knee when you are pulling the leg back.

In reviewing the research on training studies of deep water running, it seems the programs that are most successful are the ones that incorporate high-intensity intervals. Sorry folks … it seems you need to actually try harder in the water than you would on land to make this work! By using interval training, you can work in some high-intensity efforts with some easier efforts in order to extend the time in the water. Your high intensity efforts may only be about 10-seconds long … try to work up to 30-seconds.

In an attempt to try to avoid running injuries, you might even want to add some deep water running to your training program to supplement your on-land training. Just remember: Too Much Change Too Soon can lead to injury. Give your body a chance to adapt and it will.

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New Year’s Day Polar Dip

Join XCELL for our

Annual New Year’s Day Polar Dip
January 1, 2017

12 Noon

The Village


Lake Las Vegas

What is it?

The Polar dip is a great way to start your New Year off!  Participants dip into the water at The Village at Lake Las Vegas.  Some may wish to swim a short 200 yard course.  It is a very energizing experience.  We have options for just about any way you would like to handle the challenge.


How do I do it?  

Sign up below and then show up on New Year’s Day.  The traditional way is no wetsuit: jump in and jump out.  You can warm up under the heaters provided by Lake Las Vegas and get changed into dry clothes in the Village rest rooms.

Finisher certificates for all participants and awards for best costume and special categories.

 Costumes strongly encouraged.  This is Vegas, I am SURE we have some creative types that pull off some fun ideas!  That has certainly been the case in the past.

Bring dry clothes, towels, confidence.

Leave home – doubts, sanity.

Seasons Market is generously supplying those who brave the waters

FREE  Hot Chocolate and Coffee.

Lake Las Vegas is supplying heaters.


A portion of your fee goes directly to Safe Nest.

Safe Nest is Nevada’s largest and most comprehensive charity devoted solely to domestic violence issues.  If you care to donate gently used clothing please bring them to the Dip and we will make sure they get to Safe Nest.


Cost: $10.00 prepay Team XCELL

$12 Guest

$15 on site

New Year’s Day Dip – Team XCELL


New Year’s Day Polar Plunge Guest



Paddleboard, kayak and lifeguard support will be provided.  Water temperature is approximately 60.

Tips for the Dip:

Do not try to get used to the cold water.  Just get in.  EXPECT to feel very cold at first and to feel like you can not breathe.  This is normal.  (Coach Mel finds none of this normal, by the way). Just force yourself to exhale.  Then either get out right away or start swimming.  You will be fine.  I will be participating as well.  Please bring a towel and dry clothes to change into.  If swimming bring a brightly colored swim cap and your goggles.


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Heart Rate During Exercise Explained

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I Dr. Mercer asked to explain heart rate to the group.

By John A. Mercer, Ph.D.
Biomechanics Laboratory, University of Nevada, Las Vegas

Why do we measure heart rate during exercise? The answer to this question seems rather obvious… but sometimes the obvious answer leads us to overlook some important physiological responses during exercise and the usefulness of heart rate can be lost.

Heart rate is simply a measure of how fast the heart is beating and typically represented in units of beats per minute (bpm). This is an easy measure to take with the availability of heart rate monitors…Polar, Garmin, Timex, Suunto, etc…there are many manufacturers of heart rate monitors and they all perform rather similarly in that you get a consistent and valid measure.

But why is it important to know how fast the heart is beating? Many people will give an answer like “It tells us how hard the heart is working.” Technically, this is not correct … to know how hard the heart is working we would need to know the blood pressure response as well as the heart rate.

We measure heart rate during exercise because it is gives us a sense of how much oxygen we are consuming. (There is a lot of physiology that I need to present to justify that statement … so hold on … here we go!) From a very basic perspective, muscles generate force to cause movement. To create force, muscles transform chemical energy to mechanical energy. Much like the engine of your car which transforms energy in fuel to (ultimately) create a force that makes the wheels move.

Muscles generate force by transforming energy anaerobically (without oxygen) and aerobically (with oxygen) to create force. You cannot exercise that long without oxygen … remember those swimming drills where you take a breath every 3 or 5 strokes? That can be hard to do for long! So let me focus on the aerobic process of generating force.

Muscles need oxygen to generate force during endurance exercise. As intensity of exercise increases, we need to consume more and more oxygen. The oxygen is used to transform chemical energy (e.g., carbohydrates, fats) to mechanical energy (e.g., movement). You take deeper and more breaths as you start exercising harder and harder in order to get more oxygen to the muscles. Oxygen needs to get from the lungs to the working muscles … that happens because of the circulatory system. Blood is pumped through the lungs to pick up oxygen, then the ‘oxygenated’ blood is pumped out to the working muscles. The muscles pull the oxygen out of the blood … and the ‘deoxygenated’ blood is pumped back to the lungs to pick up more oxygen.

If I really want to know how hard exercise is, I would want to know how much and how fast oxygen is being used by the muscles. That is the most important factor when quantifying exercise intensity because that tells how chemical energy (carbohydrates and fats) is being transformed to mechanical energy. Knowing how much oxygen is used tells us how many calories are used. In order to measure how much oxygen is being used, you would need to breath into a special mask so all the air that you
inspire and expire is measured … that’s not easy and the instruments to measure oxygen is expensive.
This is where heart rate starts to come back into the picture.

We can figure out how much and how fast oxygen is being used if we know three things (for those of you that want to read more on this, just google ‘Fick Equation’):

1. How fast the heart is beating (i.e., Heart Rate).
2. How much blood is pumped with each beat (we call this ‘Stroke Volume’).
3. How much oxygen is pulled out of the blood by the working muscles.

What is really interesting is that each of these parameters change in a predictable manner as exercise intensity increases. That means that we could measure any one of the parameters and then predict how much and how fast oxygen is being used. That’s cool … because of the three parameters, the easiest one to measure during exercise is Heart Rate!

So … why do we measure Heart Rate during exercise? To get a sense of how much and how fast we are using oxygen! That’s it … nothing more to it.

Now, many people know that heart rate can be different on different days even if we are running the same speed. That can happen because heart rate is only 1 of 3 parameters that determines oxygen use! Heart rate (by itself) does not always tell us how much oxygen is used because either stroke volume and/or the amount of oxygen pulled out of blood by the muscles can change.

Here’s an example: When you watch a scary movie, typically, your heart rate increases … but that does not mean you are using more oxygen. When you get scared, the stroke volume can decrease while heart rate increases … which means there may be no change in oxygen consumption!

The same thing can happen during exercise. Sometimes, the amount of blood pumped with each beat can vary between days (when you are running the same speed) or even between types of exercise. For example, your heart rate is probably a bit lower when cycling vs. running. Part of that has to do with the position of the body that can influence stroke volume (how much blood pumped with each beat).

Because stroke volume changes, heart rate also changes … so when we predict the oxygen used during cycling using heart rate only, we have to use a different equation than running because stroke volume changes. The same thing happens when we swim … putting the body in a horizontal position and having water pressure pushing on the body influences stroke volume … and that means heart rate will be different for a given oxygen consumption.

This does not mean that heart rate is not a good indicator of intensity … instead, it is important to understand that we are really trying to get a sense of how much oxygen is being used and heart rate is a good predictor of that (but it is only 1 of 3 factors that influences oxygen used).

So what can you do with this information? Heart rate is a really easy measure to define exercise intensity … because of that, your coach may tell you to exercise in different ‘training zones’ based on heart rate or, you may communicate to your coach what your heart rate was during a workout. In both of these examples, heart rate is being used to describe the intensity of exercise … and this works well when there is a good understanding of the limitation of heart rate in predicting oxygen used.

But remember, heart rate is one of three factors that is used to understand oxygen cost of exercise … and that is the critical parameter that defines exercise intensity.

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How many calories are used to run a 5K?

By John A. Mercer, Ph.D.
Biomechanics Laboratory, University of Nevada, Las Vegas

Ask this question and you’ll usually get an answer that you use more calories if you run faster … but the answer is a bit more complicated (and probably unexpected!) than that and this simple question can lead to some in depth discussion of physiology and biomechanics.

Let me give the short the answer up front … then there is the long answer below! The number of Calories to run a 5 K is the same no matter how fast you run. What does change as you run faster is the rate of Calories used … but the total amount is the same to cover a given distance.

Part of the explanation for this is that as you run faster, the time to cover a distance decreases … so even though the rate of Calories used increases, the total amount of Calories to cover a distance is the same. Really important note: This is only concerning running … the number of Calories used to cover a distance while walking is a different answer.

To calculate the number of Calories to run a distance, you need to know your body weight and the distance you ran. You can find ‘calorie calculators’ on the web really easy … here is a simple equation:

Calories = (body weight in pounds) x (distance in miles) x (0.695)
(Note: Most equations will use a constant between 0.69 and 0.80)
So, let’s say a 200 lb runner ran 3.1 miles … the total number of Calories is:
Calories = (200 lb) x (3.1 miles) x 0.695 = 431 Calories

Notice that the time to complete the 5 K does not enter the equation … if the runner ran faster, he will use Calories at a faster rate but end up using the same number of Calories overall. Let’s go the other way and talk about how fast Calories are being used.

Consider the same 200 lb runner. If he were running at 4 mph, he would be using Calories at a rate of about 9.27 Calories per minute (this is from some published data). If he ran at 6 mph, he would be using Calories at a rate of about 13.90 Calories per minute. If he runs 3.1 miles, he would take 46.5 minutes running at 4 mph and 31 minutes running at 6 mph. Let’s do some math:

Total Calories = (Rate of Calories) x (time ran)
At 4 mph: (9.27 Calories/min) x (46.5 minutes) = 431 Calories
At 6 mph: (13.90 Calories/min) x (31 minutes) = 431 Calories

The total Calories is the same! Now, there are some finer points to these calculations … and sometimes there is an adjustment to the number of Calories used based upon whether the Calories come from fat or carbohydrate … but the bottom line is that the total number of Calories is still fairly consistent for a given distance.

The rate of Calories used tells us ‘how hard’ the exercise is and increases with running speed … but the total amount of Calories used is the same for a given distance ran regardless of speed (because you cover that distance in a shorter time when you run faster).

This concept is really useful when planning out your long runs … just calculate the total number of Calories based upon distance and then be sure to take in the right amount of fuel. Also, if you want to increase the total Calories you use during running – you have to run farther (not faster).

Click here to download the complete article and “long” answer.

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