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Exercise Questions

  • I am feeling sick. Should I exercise and sweat it out or simply rest?

    Sweating it out is the macho way of getting over a bug however often not the smartest way.

    Thing is, when you exercise you place a lot of physical stress upon your system. The higher the intensity, the more stress induced. So if exercising with a bug, your body is now trying to repair itself from both the exercise and the bug! Your immune system therefore has less resources allocated to it in order fight off the bug - ultimately giving the infection an opportunity to spread throughout the body.

    Ultimately it really comes down to the individual. You need to know how your body feels and if it is capable of any exercise at all. If your sickness is only very mild, then you may be able to get away with an exercise session, possibly at a lower intensity depending upon the degree of the symptoms.  As for any severe sickness, forget it - you will be inducing more harm than good.

    If ever in doubt, speak to your GP and always take your doctors advice!

  • How are different muscle fibre types recruited during exercise?

    The human body is composed of two major types of muscle fibres:

    1. Type I (Slow twitch) - red muscle fibres (due to their abundant supply of blood)
    2. Type II (Fast twitch) - white muscle fibres

    Slow twitch fibres are utilised for endurance aerobic activity.  Fast twitch fibres are utilised for anaerobic activity, for example strength or hypertrophy resistance exercise.  As the names suggest, fast twitch fibres contract at a much faster rate than slow twitch fibres - approximately 2-10 times faster depending on the muscle group.  The faster the rate that the muscle can contract, the more force that can be exerted.

    Taking a closer look, we can further break down muscle types into the following categories:

    1. Type I
    2. Type IIa
    3. Type IIb/x (the x is used to indicate a range of other muscle fibre isoforms in this catgegory)

    Here you will see that type II (fast twitch) fibres are broken down into several sub-categories.  Type IIa and type IIb/x muscle fibres are two separate categories because they are utilised in different scenarios.  The three muscle fibres are utilised as follows:

    Type I muscle fibres are recruited as the primary fibre for light force production (such as endurance training)
    Type IIa muscle fibres
    are recruited as the primary fibre for moderate force production (such as hypertrophy training, eg. 9-12 reps)
    Type IIb/x muscle fibres are recruited as the primary fibre for heavy force production (such as strength and plyometric training eg. 1-5 reps)

    One common misconception is that during strength training, for example, only the type IIb/x muscle fibres are recruited.  Whilst they are the primary muscle group in this form of exercise, they are also "supported" by type I and type IIa muscle fibres.  Similarly with hypertophy training, type IIa is supported by type I fibres.  Let's analyse a squat to summarise this information:

    50 rep squat - Type I only
    12 rep squat (to failure) - Type I + Type IIa
    3 rep squat (to failure) - Type I + Type IIa + Type IIb/x

    As is suggested above, strength training will recruit the most muscle fibres in order to produce the very significant forces required.

  • Is lactic acid (or lactate) bad? Is it why my muscles burn (acidosis)? What about DOMS?

    Lactic acid (or lactate) is an essential molecule found within the muscle cells in order to aid recovery.

    Within the last ten or so years, science has determined that lactic acid is actually not responsible for the burning sensation within the muscle after anaerobic training.    These findings were contrary to previous beliefs.  In actual fact, lactic acid is what aids in reducing that burning sensation within muscle cells (or muscle fibres).  The burning sensation is scientifically known as acidosis (since the burn is due to an acidic environment forming).

    So how does it work?  The chemistry is fairly complex and tedious, so let's just stick to the basics:

    1. Your muscles require ATP (adenosine tri-phosphate) which is a primary source of energy found within the body.  Without ATP, your muscles would not work at all!

    2. When you initiate a contraction of a muscle cell (or muscle fibre), the energy for this is derived from splitting ATP into ADP (adenosine di-phosphate) plus Pi (inorganic phosphate) through hyrolisation.  This process results in the accumulation of H+ ions.

    3. The accumulation of H+ ions creates an acidic environment which is responsible for the "burn" sensation experienced particularly with anaerobic exercise.  Eventually the H+ ions will accumulate to the point where the environment is so acidic, the muscle will fail to work.  This can be one reason why you may experience muscular failure during resistance training.  This is a safety mechanism the body employs to prevent overloading the muscles to the point of injury.

    4. A molecule called pyruvate acts as a "buffer" that comes and cleans up H+ ions within the muscle fibre.  Pyruvate binds with 2 of the H+ ions to form lactate.  This process neutralises the environment and allows muscle function to return to normal.

    As a result, lactate (or lactic acid) is not directly responsible for acidosis.

    You can improve the efficiency of this process by training at a high intensity for short periods of time (either steady-state or interval training).  The more efficient your muscles are at dispelling acidic build-up, the more efficient they will work when placed under overload from exercise.

    Lactic acid is also not responsible for DOMS (delayed onset muscle soreness).  DOMS occurs due to microscopic muscle damage as a result of exercise - not from the build-up of the lactic acid that helps to reduce the acidity of muscle cells.

  • I have just begin HIIT (High Intensity Interval Training) cardio. How much more fat should I expect to lose? Also, what have been your experiences with HIIT?

    Hey Sally...I've been training with HIIT cardio for about 3 years now.  Whilst there was a period in my training where I stopped it altogether to focus on weights, for the last 18 months I've been really consistent with it (3-7 times per week). 

    Fat wise, studies have shown anywhere from 3-9x more fat relative to steady state exercise.  I wrote an article on HIIT training which cites an article that determined 9 times more fat is burnt:

    The Fat Burning Zone  

    It's hard to say precisely how much more fat you can expect to burn as this obviously depends upon many variables.

    My experience with the cardio is, initially it is very tough - mentally and physically.  You really test yourself every single time and I am yet to find a tougher (and more excruciating) form of exercise.  But if you apply yourself over an extended period of time, you develop a really strong discipline that emanates in other area's of life.

  • What will result in greater fat loss and muscle loss, HIIT cardio or low intensity endurance cardio?

    HIIT cardio will result in significant fat loss - far more significant than 60-70% max heart rate. Lower intensity exercise utilises fat as a primary energy fuel source during exercise, but the net adipose tissue (fat tissue) breakdown is far greater with HIIT cardio over a 24 hour snapshot.

    Meanwhile with regards to the breakdown of muscle mass, HIIT cardio can actually produce an anabolic effect with regards to muscular hypertrophy (building muscle). Of course, significant amounts of HIIT cardio (or any cardio for that matter) will result in significant muscle atrophy (breakdown). But this simply is achieved through a caloric defecit - and could be just as effectively achieved through a diet deficient in calories.

    It's very easy to get confused on this topic, particularly with the infamous "fat burning zone"...gah that is something I have a real beef about.

    For more reading on the subject, check out these articles:

    The Fat Burning Zone

    (Begin with the one above, it's an article I had published in several fitness/bodybuilding magazines and provides a more general overview on the topic. The articles below analyse the subject in greater detail.)

    Myths Under the Microscope - Fat Burning Zone

    Myths Under the Microscope - Fasted Cardio

    Myths Under the Microscope - Final Discussion

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