Do, Try, Skip: Foam Rolling, Group Exercise, Running Music

Do you need music to perform
at your best?
Photo: competitor RUNNING

This series is intended to provide an informative and entertaining look at common practices in endurance sports.  The views expressed here are my opinions based largely on a combination of professional experience as an exercise physiologist and personal experience as an endurance athlete.

Sports training practices change over time.  Looking back a generation (or more) some things seem preposterous now.  But in their day and time they might have been considered cutting edge.  This "Do, Try, Skip" series will look at current popular training practices and provide guidance based on science (if available) and personal experience.  Today we look at three popular training practices; foam rolling, group exercise, and listening to music while running.

Foam Rolling: DO
The practice of foam rolling is something many athletes (myself included) understand to be important but few consistently perform.  Interestingly, the technique may have originated as an inexpensive way for Broadway dancers to simulate deep tissue massage on tight aching muscles.  But the practice was undoubtedly popularized by National Academy of Sports Medicine founder and physical therapist Michael A. Clark.  Referred to as self-myofascial release stretching (SMFR) in his 2002 manual Optimal Performance Training for the Performance Enhancement Specialist the technique is defined as "the process of using bio-foam rollers and/or "The Stick" to improve soft-tissue extensibility".  This type of stretching utilizes the autogenic inhibition theory to correct length and tension imbalances of the muscles.  

Self-Myofascial Release of the TFL.
From livejacked.com

Autogenic Inhibition
The key to understanding how foam rolling works lies with muscle spindles and Golgi Tendon Organs (GTO).  Muscle spindles lie in parallel with muscle fibers and sense the rate and change of muscle lengthening.  When stimulated they may cause the muscle to contract resulting in "trigger points".  This can occur during times of sudden increases in training volume or new training loads (ie. change of surface or terrain).  A chronically shortened (ie. contracted) muscle not only may cause discomfort, but it is also less effective at producing force and may affect how the other soft-tissues nearby act.  

The GTO is a proprioceptive sensory receptor organ located within the junction between the muscle and the tendon and is highly sensitive to changes in tension and the rate of tension change.  When you use your body weight on the foam roller you are placing tension on the musculotendinous junction of that muscle and stimulating the GTO.  With enough stimulation, the GTO may "turn off" the muscle spindles causing the tight muscle to relax, unwind, or "unknot".  This occurs when the neural impulses sensing tension (from the foam roller) are greater than the impulses causing muscle tension (from the tight muscles).

So when and how do you use the foam roller?
Foam rolling should be seen as a form of stretching.  Specifically as a corrective flexibility modality.  When used to correct muscle imbalances (length & tension) it is best performed in both the pre- and post-workout periods.  To obtain the optimal benefit from the technique place a tolerable amount of body weight pressure on the "tender/trigger points" of the muscle and hold for approximately 30-90 seconds.  This provides adequate time for the GTO to begin to inhibit the target/offending muscle spindles.  It's worth noting that other devices may be used to perform the technique including a lacrosse ball, medicine ball, or other handheld devices.  

IMPORTANT NOTE:  While foam rolling is generally safe, it should not be performed by persons with heart failure, kidney failure, other organ failure, bleeding disorders, or contagious skin disorders.  If you have any doubt whether or not the practice would be safe and appropriate for you, check with your physician first. *From NASM

Group Exercise: TRY
There is little doubt that to improve sport-specific performance you must spend a considerable amount of time performing that sport.  However, the cumulative effects of repetitive movements patterns can result in overuse-associated soft-tissue breakdown and subsequent forced rest.  Two common ways of reducing the frequency and potential impact of repetitive movement patterns are cross-training (ie. cycling for runners and running for cyclists) and complimentary-training practices (ie. strength & mobility training).  While these activities are unquestionably important to the sustained health and performance of an endurance athlete, there are often barriers to participation.  One common barrier is the perception of lack of mastery.  None of us want to look or feel like we don't know what we are doing.  This may be the case for an endurance athlete not familiar with either cross-training or complimentary-training activities.  Here's where friendly and supportive instructor-led group exercise classes fill an incredibly important role.  

Spinning Bikes.
From nursegail.com

Group exercise can generally be categorized in one of four ways; aerobic, strength, bodymind, and specialty.  All have potential benefit to the endurance athlete.  Let's take a look and some common examples and how they might fit into an endurance training program.



Indoor Cycling (aka. Spinning)
Type: cross-training
Category:  aerobic

While it's always better to be outside rather than inside, indoor instructor led group cycling classes offer runners a non-impact alternative to their high impact sport.  

Kickboxing
Type:  cross-training
Category: aerobic

This instructor-led group exercise format is a mix of boxing moves, martial arts, and aerobics that combine to provide a high-intensity training session and is great for cyclists as it gets them out of forward trunk/hip flexion and upright on their feet.  

Orangetheory Fitness®
Type:  cross-training & complimentary-training
Category: aerobic & strength

Led by qualified personal trainers this one hour exercise class uses heart rate to monitor high intensity interval training (aerobic & strength) giving users a targeted and effective training experience.  Because of the use of both aerobic activities (running, cycling, rowing) along with strength exercises it covers both the aerobic and strength categories. 

Yoga
Type:  complimentary-training
Category:  bodymind

The spiritual element of yoga separates it from most other instructor-led group exercise activities.  And while the bodymind benefits are translatable to all endurance athletes, it's ability to improve mobility may be it's greatest physical benefit.  

Running Music: SKIP
What's a blog without occasionally dipping your toe into a heated debate once in a while?  I am well aware that many runners use music while running to help them either escape from the drudgery or motivate them to push harder.  Both of these rationales are valid yet they don't overcome the overwhelming negatives associated with the practice.  Listening to music while running is considered a dissociative behavior.  That is to say, it's a way to disconnect from the activity.  This disconnection is both mental and physical.  But being connected to the activity provides a wealth of important and immediate feedback that helps to assure the activity is both safe and effective.

Safety
Whether on or off-road you are likely to be sharing space with other people.  These people are typically traveling by vehicle, bicycle, or on foot.  In each case there may be a need for you to yield the right of way.  When being approached from behind it is very difficult for you to be fully aware of your surroundings while listening to music.  Portable music devices today are typically quite inconspicuous and may not be noticeable to others around you.  This could lead to a dangerous scenario of an overtaking motorist (on road) or cyclist (on trail) attempting to signal their intent to you but to no avail.  

Efficacy
Your ears provide important feedback while running.  Running economy may be improved, in part, by soft quiet foot strikes.  Listening to music while running makes it impossible to gain this valuable feedback.  Lastly, many running events either discourage or prohibit the use of headphones due to liability concerns.  If you are conditioned to listening to music in training to help you "get through the tough times", you may be at a distinct disadvantage without it during a race.  

Let me be clear, there is a difference between listening to music while running outside versus listening to music while running inside on a treadmill.  Running inside on a treadmill is drudgery and anything you can do to take your mind off of the activity is probably helpful.  Just make sure the music you've selected doesn't get you so fired up that you miss the objective of the workout (ie. easy on easy days or target effort).  

Optimal Performance Weight For Endurance Athletes

Using total body weight alone is
like the cover of a text book.  It
gives you some idea of what's
inside but lacks important detail.

 "Never be fooled by what you see on the outside because on the inside it's often a different story." ~Anonymous

Human performance results from a complex interaction of physical, psychological, and nutritional variables. Your "optimal performance weight" is one of those variables. Let's drill down a little deeper into the topic.

Optimal Performance Weight

Body weight is an incredibly sensitive topic to discuss. Various societal pressures have increased the prevalence of disordered eating and exercise behaviors in young people. Some estimates suggest there are approximately 30 million US adults struggling with an eating disorder with 95% of them between the ages of 12-25. Female athletes make up a disproportionate percentage of that group. Many endurance athletes have experienced an eating disorder before or perhaps are struggling with one now. It is for that reason that I approach this subject very cautiously and in the spirit of supportive guidance rather than with disapproving judgement.

Body weight is inextricable related to endurance performance. More specifically, body composition (lean body mass and fat mass) is linked to endurance performance. But no online "optimal performance weight" calculator can determine that for you. Your optimal performance body composition can only be determined by consistent data collection over time. Here's how it works.

Body Composition
Your total body weight alone is like the cover of a text book; it gives you some idea of what's inside but lacks important details. With respect to body composition those details include lean body mass and percent body fat. If you're interested in optimizing endurance performance you should consider measuring your body composition routinely. These periodic body composition assessments create body accountability and data points. When assessing body composition consider the following guidelines;

1.) Assess Monthly
More frequent assessment is less sensitive to actual changes in body composition and more sensitive to daily or weekly fluctuations in body water.

2.) Standardize
By creating the same testing conditions (time of day, clothing, etc) you significantly reduce the error associated with the testing conditions.

3.) Testing Considerations
When you test make sure that you haven't exercised or eaten for at least three hours prior to the assessment and always on an empty bladder and bowel (ideally).

Commercial body fat scales are now both widely available and affordable. Most use "bioelectric impedance" technology which has been around for decades and highly correlated with the gold standards for this procedure (skinfold and plethysmography).

Performance Outcomes
Once you are in the habit of collecting lean body mass and percent body fat data the next step is to correlate it to endurance performance. There are a few important things to consider. First, understand that body composition naturally fluctuates throughout the year and/or training cycle. Differences in eating and activity patterns during the winter months and off-seasons tend to result in natural and acceptable increases in percent body fat during these times. Secondly, we must always account for the effects of aging on both performance and body composition. That is to say, you should keep your comparison of body composition and performance to the last 3-5 years. Anything beyond that becomes an unreasonable and unrealistic comparison and sets you up for discouragement and resultant demotivation. Lastly, standardize the correlation by choosing an event or workouts that is both relevant and repeatable.

My Experience

The last four years of body fat and Orchard Cross
results clearly shows that for me; leaner is faster.

This graph is the last four years of my percent body fat and cyclocross performance. The body composition data was collected on a Tanita body fat scale once a month (I've actually been collecting the data monthly for over a decade). The performance data is from a local cyclocross race (Orchard Cross) that I've done for a number of consecutive years and represents the finish points in my Category 4/5 40+ race. For those not familiar with cyclocross, the lower the finish points the better the performance relative to the rest of the field. There are a few important things to note from the graph. The first is that you can clearly see seasonal fluctuations in percent body fat with the winter months generally representing the higher percent body fat values. Secondly, there appears to be a direct correlation to my percent body fat and my Orchard Cross results. In other words, the lower my percent body fat, the better the performance result (in lower points) at that specific race. While this really isn't a surprise, it's very helpful for me to see it in black and white (and red). This graph clearly demonstrates that my 50 year old optimal performance body composition is around 10% body fat. And just as importantly, I know exactly the dedication it takes to reach this level.

Please remember that this value is highly individualized. Your optimal performance body composition is uniquely yours and you must collect adequate amounts of data to determine that value.

Training Interference: Kicking It Down The Road

If you can't get in today's workout
should you kick it down the road?

"Why do today what you can put off until tomorrow?"  ~Anonymous

The variable of interference is an integral part of every endurance training plan.  In every day practice the concept helps to answer the question, "If I miss today's training unit should I push it to tomorrow?".  The answer is almost always "perhaps", but let's look at why.

In the programming of endurance sports training, interference implies that one training unit has the potential to impact another training unit.  The magnitude of this interaction almost always is directly related to the time proximity of the two training units.  That is to say, the closer the training units are stacked together with respect to time, the greater the potential for them to interact.  When training programs are designed, this relationship between training units is fairly precisely orchestrated.

For simplicity let's categorize interference three ways; maximal, potential, and minimal. An example of all three is depicted in the training log below.

Maximal Interference
When performed on the same day, two training units have great potential to interfere with each other.  The type, duration, and intensity of the training unit will determine the amount of time needed for recovery (complete or incomplete) and therefore the magnitude of interference exerted on the subsequent training unit.  In this example, a running-specific hill workout precedes a mobility/strength training unit.  Because this training cycle represents a specific preparation phase for an upcoming event (within 4-8 weeks), running is given priority over mobility and strength development.  When two training units are scheduled and performed on the same day it can be assumed that the first training unit will maximally interfere with the subsequent training unit.  Sometimes there is an attempt to avoid this interaction (as in the case of scheduling the running unit first), and sometimes the interaction is used purposefully (as in the case of pre-fatiguing the sport-specific soft-tissues with "doubles").

Potential Interference

A common program design philosophy includes microcycle variability.  This is seen as following "hard" days with "easy" days to give the body's adaptive mechanisms a chance to do their work.  When multiple hard efforts are scheduled in sequence, not only is there less time for important training adaptations to occur, but the risk of overreaching is considerably higher.  In the example above, Thursday's steady-state workout is scheduled forty-eight hours prior to Saturday's long run.  This design is described as "potential interference" in so much as there is likely to be some carried fatigue from Thursday without compromising Saturday's training unit.  This carried fatigue is both purposeful and potentially important with regard to sport-specific performance.  In other words, marathon and ultramarathon sports have both a strength endurance and metabolic endurance component.  Performing Saturday's long run on some carried fatigue helps to prepare the athlete for the physical and energetic demands later in races.

Minimal Interference

Lastly, there are times in which training units are scheduled to minimally interact with each other as in the case of these Saturday long runs.  Although often this more a function of time availability, it does end up serving an important design benefit.  Training units of two hours in duration or longer, place significant stress loads on the body.  This includes the structural components (ie. musculoskeletal system), bio energetic systems (ie. glycogen and fat), and immune system.  The ability to successfully complete these long training units is vital to sport-specific performance.  Therefore while some carried fatigue is beneficial (as in the potential interference example above), an excessive amount of carried fatigue not only potentially compromising the successful completion of the training unit, but is also significantly increases the risk of soft-tissue injuries and illness.

In summary, because most weekly training schedules often use all three forms of interference, be careful when you "kick a training unit down the road" by moving it to the next day.  

Do, Try, Skip: Mobility Exercises, Pickle Juice, Ice Baths

Pickle juice contains a
chemical compound that just
may reduce cramps.

This series is intended to provide an informative and entertaining look at common practices in endurance sports.  The views expressed here are my opinions based largely on a combination of professional experience as an exercise physiologist and personal experience as an endurance athlete.

Sports training practices change over time.  Looking back a generation (or more) some things seem preposterous now.  But in their day and time they might have been considered cutting edge.  This "Do, Try, Skip" series will look at current popular training practices and provide guidance based on science (if available) and personal experience.  Today we look at three popular training practices; mobility exercises, pickle juice, and ice baths.

Mobility Exercises: DO
Endurance athletes spend a tremendous amount of time performing repetitive movements as they train for their sport(s).  And while the specificity of training principle states that to be a "better" runner you must run (or cyclist you must cycle), focusing all your attention on these movement patterns can create muscle imbalances that often lead to overuse injuries and time away from training.

Mobility is the ability to move quickly and easily.  It's clearly an important attribute to sport performance.  When we spend adequate amounts of time participating in our sports we develop specific adaptations that improve performance.  Unfortunately, these sport-specific movements (running or cycling) involve relatively limited range of motion in a handful of the articulating joints.  Over time the soft-tissues that support or move the joints can become shortened and dysfunctional.  These imbalances can cause a cascade of problems not the least of which is improper positioning of the joint capsules which may result in a reduced ability to generate force.  And for an endurance athlete this means one or both of two things; 1.) reduced sport performance and 2.) increased risk of injuries.

Adding mobility exercises to your training routine can help to improve soft-tissue and joint dysfunction caused by overused and shortened locomotion muscles.  Do this routine daily to improve mobility and sport performance.  Video courtesy of Kim Nedeau.  Check out her informative video series for endurance athletes.  

Pickle Juice: TRY
Every endurance athlete has had the experience of performance-limiting excruciating muscle cramps during a race.  And interestingly enough these sometimes happen in the context of cool weather and adequate hydration tactics.  In 2011, during my last attempt at the infamously brutal 7 Sisters Trail Race (Amherst, MA) on a cool and overcast day less than four miles from the finish I experienced a double quad cramp the likes that I had never before and not since ever felt.  It was so intense that I came to a complete stop and with legs that failed to bend at the knee fell over to the ground.  At the same time I was trying to fix the problem I was also quickly taking inventory of the possible causes.  The weather was perfect for a May trail race and I had been hydrating and eating like a champ.  This particular trail race, with it's unrelenting ups & downs, can be brutal on the quads.  In my effort to run a sub 2:30 I had hammered the first half attacking the descents with reckless abandon and fury.  All of that eccentric "braking" action during the downhills eventually took it's toll on the way back.

Research into the causes of cramps have recently led scientists to determine that the nervous system is one common and likely cause.  Alpha motor neurons are nerves located in the brain stem and spinal cord.  These nerves direct the skeletal muscles by telling them when to contract.  But when muscles fatigue the activity of these alpha motor neurons increases and stimulates the muscles to maintain a sustained contraction (ie. muscle cramp).  Skeletal muscle fatigue is a complex and multi-faceted event that may involve one or all of the following variables; repetitive muscle contraction, increased exercise intensity, increase exercise duration, environmental conditions (heat/humidity), and lack of training.  It is also suspected that repetitively contracting a skeletal muscle in a shorten state may also lead to increased alpha motor neuron activity.  Not surprisingly, during running the hamstrings, quads, and calves all contract in a shortened state.  These muscles tend to be the most common ones to cramp for this reason.  It's therefore not terribly surprising that my quads cramped after running the first half of 7 Sisters (particularly the descents) much harder than my training had warranted.      

So with some knowledge of why muscle cramps happen, the most important question then is what do I do to fix them?  Pickle juice has recently emerged on the ultra running scene as a somewhat mythical potion.  Athletes have retold stories of how it magically made their cramps disappear but how it works may surprise you.  While it's true that pickle juice is high in electrolytes, once consumed it may take up to 30 minutes for it to empty from the stomach and affect electrolyte levels at the site of muscle cramp.  This fact seems to belie that it works almost immediately.  Evidence now suggests that the feeling that you experience at the back of your throat when you drink this noxious pickle juice may be the secret to it's effectiveness.  

It appears that the chemicals in pickle juice (as well as in chili's, mint, cinnamon, ginger, & mustard) may very well be stimulating what are known as transient receptor channels (TRPs).  These excitable cells in the back of our throats convert chemical messages into electrical signals that help to control a number of sensations like pain, taste, hot, cold, and pressure.  These channels are activated by the chemicals in pickle juice and have the effect of reducing the activity of the alpha motor neurons and therefore relieving the cramp.

While the research is very promising and still evolving, the anecdotal evidence supports giving pickle juice (and similar products) a try.  Ideally it's best to prevent muscle cramps in the first place, but if you find yourself with a hyper-locked double quad cramp and someone offers you a shot of pickle juice...try it.

Ice Baths:  SKIP
We've all been tempted, mostly by peer pressure, to slip into a tub of icy water following a grueling race with the promise of accelerated recovery and reduced muscle soreness.  And despite as much folklore as the practice has received, it's benefits were actually questioned nearly a dozen years ago.  Subsequently there have been competing viewpoints on the subject with both camps (ice baths good vs. ice bath phony) digging in their heels.  

A number of systematic reviews of the literature have been done without a clear consensus on the impact of cold water immersion in endurance athletes resulting in the intended anti-inflammatory response.  In addition, many sports scientists are split on the theory of inflammation with some suggesting it's the root of muscle damage and therefore must be controlled while others suggesting that it is an integral part of the healing process and must be allowed to occur.   

Adding to the confusion are the professional athlete and ice bath advocates like Mo Farah, Ryan Lochte, and Lebron James who all purportedly use the practice.  It's completely conceivable that these and other followers feel a positive difference when they use ice baths.  These and other professional athletes are looking for any tiny advantage they can get as the margins for success are razor thin at that level.  Assuming there aren't any physical risks, if it turns out that the effects of cold water immersion are only placebo (ie. in their minds) then it may still be an advantageous.  

For the endurance athlete tempted to slip into that icy tub for the first time with the hopes that their recovery will be enhanced consider that the practice is not only incredibly uncomfortable, but the until the scientific community can come to a consensus it's best to skip it.

References;
1.  Mobility - Moving Beyond The Buzzword, by Jim Shepherd
2.  6 Exercises For Maximum Mobility, Outside Magazine
3.  Does Pickle Juice Relieve Muscle Cramps?, The Cooper Institute
4.  Holy Cramp!  The Science of Exercise-Associated Cramping
5.  A Recovery Ice Bath Isn't (Always) Such a Great Idea, Outside Magazine   

Influenza & The Endurance Athlete

When it comes to the
influenza virus there's almost
nowhere to hide.

"I am sick and tired of being sick and tired."  ~Fannie Lou Hamer

Have you noticed that "something's going around" lately?  There's a better than average chance that you or a training partner has been sidelined with an illness in the last four weeks.  While athletes are generally the healthiest and heartiest in a population, they too are susceptible to catching what's going around and this time of year that generally means the flu.

According to the Center's for Disease Control and Prevention, influenza (the flu) is a contagious respiratory illness caused by influenza viruses.  While there are four types of the virus (A, B, C, & D), human influenza viruses A & B are responsible for seasonal epidemics almost every winter.   Influenza A viruses are divided into subtypes based on two proteins on the surface of the virus;  the hemagglutinin (H) and the neuraminidase (N). There are 18 different hemagglutinin subtypes and 11 different neuraminidase sub types. (H1 through H18 and N1 through N11 respectively.)  Influenza A viruses can be further broken down into different strains. Current subtypes of influenza A viruses found in people are influenza A (H1N1) and influenza A (H3N2) viruses. *adapted from the CDC

The Flu Virus In Action
From the CDC

How It Spreads  
Scientists believe that influenza viruses spread mainly by tiny droplets made when people with the flu cough, sneeze, or talk. These droplets can land in the mouths or noses (ie. respiratory system) of people who are less than six feet away. Less often, a person might also get flu by touching a surface or object that has flu virus on it and then touching their own mouth, nose, or even their eyes.  Most healthy adults may be able to infect other people beginning 1 day before symptoms develop and up to 5 to 7 days after becoming sick. Children may pass the virus for longer than 7 days. Symptoms start 1 to 4 days after the virus enters the body. That means that you may be able to pass on the flu to someone else before you know you are sick, as well as while you are sick. Some people can be infected with the flu virus but have no symptoms. During this time, those persons may still spread the virus to others.  *adapted from the CDC

What Are The Symptoms?  
People who have the flu often feel some or all of these signs and symptoms that usually start suddenly, not gradually:

• Fever* or feeling feverish/chills (*not everyone with the flu will have a fever)
• Cough
• Sore throat
• Runny or stuffy nose
• Muscle or body aches
• Headaches
• Fatigue (very tired)
• Some people may have vomiting and diarrhea, though this is more common in young children than in adults.

*adapted from the CDC

"The Flu Season"
From the CDC

The Impact To Endurance Athletes
While there are no ideal times to be sick, there are certainly times that are worse than others.  According to the CDC, the peak months for flu activity are December through March.  This time period represents important sport-specific preparation for spring events including marathons.  During this time every training unit is critical as volume is gradually increased toward key benchmarks.  Missing a single training unit will have little impact on the accumulation of fitness, but missing a week or more of training may result in a setback and prompt revisions to the training plan and reassessment of goals.  

Preventing The Flu
The CDC recommends a yearly flu vaccine as the initial and most important step in protecting against flu viruses.  As discussed earlier, there are many subtypes of the virus and all can cause influenza.  Scientist develop the vaccine each year to handle what is estimated to be the most common type(s), but it is never a guaranteed measure against getting sick.  Athletes should also consider the following every day practices to reduce the likelihood of getting the flu;

• Try to avoid close contact with known sick people.
• Limit the time spent in close contact with large groups of people.
• Wash your hands often with soap and water. If soap and water are not available, use an alcohol-based hand rub.
• Avoid touching your eyes, nose and mouth.
• Clean and disinfect surfaces and objects that may be contaminated with germs like the flu.

Once You're Sick

Despite getting the flu shot and practicing good prevention measures, athletes sometimes get sick.  Identifying and dealing with the illness appropriately may lessen the burden on those within your immediate environment and help you return to training safely and effectively.

If during the months of December through March the symptoms listed above come on suddenly following exposure to individuals with known influenza there is a very good chance you have also contracted it.  Although because there are other respiratory illnesses that can also cause flu-like symptoms it's virtually impossible to diagnose the virus without a test.  Therefore, flu-like illnesses in otherwise healthy athletes are essentially handled the same way.

Most athletes with the flu (or other flu-like illnesses) have a mild illness and do not require medical attention or anti-viral medications.  If you do get sick in most cases it's best to stay home, rest, and avoid contact with other people.  Some individuals are considered high risk for developing flu-related complications and should consult their healthcare providers as soon as symptoms develop.  A full list may be found on the CDC website.

In an effort to lessen the burden on others and hasten your return to activity, it's wise to follow these practices when you're sick with flu-like symptoms;

• While sick, limit contact with others as much as possible to keep from infecting them.
• If you are sick with flu-like illness, the CDC recommends that you stay home for at least 24 hours after your fever is gone except to get medical care or for other necessities. (Your fever should be gone for 24 hours without the use of a fever-reducing medicine.)
• Cover your nose and mouth with a tissue when you cough or sneeze. Throw the tissue in the trash after you use it.
• Remain adequately hydrated.  Urine should be pale yellow color.
• Hold all training activities for at least 24 hours after your fever is gone or symptoms have subsided.

Returning To Training

Once symptoms have gone and you're feeling back to yourself, the next challenge is determining the safest and most effective way to return to training.  Prolonged bed rest (30 days or greater) may have a profound effect on the cardiovascular, muscular, and skeletal systems.  These changes may include reductions in VO2max, skeletal muscle force production, and bone density.  Any illness causing bed rest of this duration should result in the complete redesign of a training plan to start from square zero.  The initial priority is the safe resumption of every day physical activity to eventually include a very low volume exercise program.  This approach may take up to six months to prepare an athlete to begin a structured and more rigorous training plan.

Most layoffs for endurance athletes however are a week or less in duration.  Nevertheless, the physiologic degradation of the cardiovascular, muscular, and skeletal systems happens on a continuum and should be considered when resuming training.  It may be assumed that early remodeling of the cardiovascular and muscular systems will be of greatest importance to the endurance athlete returning to training.  If you've been "in bed" with flu-like symptoms for a week or less it may be wise to consider the following return to training guidelines;

• Missed training units should remain missed, do not push them ahead in the plan.
• The first endurance-type training unit performed after a layoff should be an active recovery or easy training unit.  Avoid higher intensity workouts on the initial day back to training.
• Strength training may need to be modified to reduce the volume by decreasing the intensity (ie. amount of weight lifted).

It takes a considerable amount of time off from training to result in significant decreases in fitness so many athletes may find their return to training fairly uneventful.  That said, it is still important to lower performance expectations in the 7-14 days following a typical layoff while physiologic adaptations occur.