Friday, 14 March 2014

My Thoughts on Aerobic Training & Hockey As It Relates To Preparation

Much of the banter and discussion regarding sports performance on the internet, conferences etc seem to focus on speed, power, and strength.  These topics are obviously very critical in the development of high performance athletes.  The one area that I always dedicate much thought and program development to is cardiovascular conditioning.  Like the afore- mentioned physical qualities, this is one that also creates much controversy and debate.  The following are my opinions on the topic based on 30 plus years in the field, and the literature that has been published, we do use this at .  Although I am going to reference the sport of hockey often, the concepts can be applied to many sports.

Ice hockey is typically defined as an anaerobic sport.  Here are the facts as we know it:

       The game is 60 minutes in length
       Shifts are made up of 30-60 second intense efforts
       Average play/player - 20 minutes or less
       Energy system usage - all
       Atp-pc - limiting factor in 5-10 second bursts
       Lactic acid - 9-11 mmol/l observed during games
       Aerobic - the higher the players vo2 max, the higher the aerobic contribution and the lower the anaerobic one.

When devising a plan to enhance the cardiovascular component of hockey, I believe it’s important to look at the energy systems that support each other (ATP-PC Lactic Acid anaerobic & aerobic), and by enhancing this with a specific focus, I can thereby enhance the whole system. 

The particular issue that I see as a common problem in the training field is that many take the concept of sport specificity too far.  For example, since shifts are generally made up of 30-60 seconds of 5-10 second repeated bursts, training should be entirely focused on intervals in this range, and more specificity can be achieved by manipulating the rest periods to achieve the energy system goal.  I.e.. 10 sec max effort with 50 second rest could be defined as a focus on the ATP-PC system, while 10 sec hard effort with 10 seconds recovery repeated 20 times would be aerobic.  Same interval different focus.

The above example could be considered very sport specific to hockey as it matches up the short bursts we typically see on the ice.  I am not convinced, being so sport specific in this particular instance is the optimal method to train. Here are my reasons why:

The game itself is as stated earlier anaerobic in nature.  So if we take an NHL pro for example, his season would begin in September with training camp, and could last until mid June if he reaches the Stanley Cup final.  This would be almost 10 months of anaerobic focused work.  This can be extremely fatiguing in addition to the stress of performing at such a high level.  If you add to this volume of yearly work (yes playing and practicing is work & volume to the body) high intensity sprint interval training, then you are asking your body to adapt to anaerobic work year round.  There is a potential negative cost to the body with this kind of continual stress placed on it. Ie. Overtraining, injury etc.

If you take into account that all of the strength and plyometric training that a hockey player will endure, this adds to the volume of total yearly anaerobic work.  In a study by, Parra et al. he showed that only 2 weeks of daily sprint interval training increased citrate synthase maximal activity but did not change “anaerobic” work capacity, possibly because of chronic fatigue induced by daily training (Acta Physiol. Scand 169: 157–165, 2000).  There is a possibility of this kind of chronic fatigue setting in for a hockey player also.  Realizing that the study was only 2 weeks long and work was every day, I am extrapolating what might happen with a hockey player’s volume of work.

I think this issue may have started with a great paper that McMaster University Professor Martin Gibala completed called Short-term sprint interval versus traditional endurance training: similar initial adaptations in human skeletal muscle and exercise performance. J Physiol 2006, 575:901–911His conclusion stated “that young healthy persons of average fitness, intense interval exercise is a time-efficient strategy to stimulate skeletal muscle adaptations comparable with traditional endurance training.”  This study although extremely beneficial does NOT address the impact on high performance athletes, and has been in my opinion been taken out of context by many in the fitness industry with the proliferation of HIT circuit style trainingSee my other blog article on the perils of this type of training It is also my belief that those who are just beginning an exercise program are not structurally capable or physiologically ready to handing high intensity exercise.
The other fact from a reference point of view that I would like to make has to do with the concept of training impacting either a peripheral or central adaptation.  In a great review article by Dave Docherty A Proposed Model for Examining the Interference Phenomenon between Concurrent Aerobic and Strength Training (Sports Medicine 2000 Dec 30 (6) he discusses whether exercise stimulus can affect the body peripherally or via a central adaptation.  It has been proposed that peripheral adaptations are stimulated through the state of hypoxia experienced by the muscle during high intensity, aerobic interval training or high intensity strength training with reps at 10 rm’s or over.  Other adaptations include increases in muscle capillarisation, mitochondrial enzyme activity and myoglobin content.  Central adaptation are those associated with lower intensity training that is associated with changes in the cardiopulmonary mechanisms.  As training intensity increases the location of adaptation appears to shift to the peripheral components with changes in muscle capillarisation, oxidative enzyme activity, mitochondrial volume and density, and myoglobin.

The illustration below details this process.

While this article looked at the interference models for concurrent strength and aerobic work, it certainly alludes to this zone of interference that I believe can cause problems for hockey players and other athletes who focus too much high intensity interval training year round.  There is clearly, important adaptations that appear to occur with low-intensity continuous training that are not observed with mixed or high-intensity training. In his review Docherty states “While the immediate effect of low-intensity high- volume training on intense exercise performance can be difficult to assess, it would appear that the insertion of these low-intensity training sessions has a positive impact on performance, despite being performed at an intensity that is markedly less than that which is specifically performed at during intense exercise competition. It is often purported that these periods of relatively low-intensity, high training volumes may provide the aerobic platform needed to facilitate the specific adaptations that occur in response to the high-intensity or specific workouts.”

In another good review by Olivier Girard titled Repeat Spring Ability (RSA) Factors Contributing to Fatigue Part 1 & 2, he states that research has shown that subjects with a greater VO2 max have a superior ability to resist fatigue during RSA (not unlike hockey), especially during the latter stages of a repeated-sprint test when subjects may reach their max VO2.   This suggests that improving VO2 may allow for a greater aerobic contribution to repeated sprints, potentially improving RSA.

With all of this information I want to be clear that I am not advocating that you train hockey players like marathoners or a Tour De France cyclist.  They do not need to be running or cycling for 2-3 hours at a time, this would be not advantageous for strength and power development.  But I believe there is enough evidence to advocate the use of aerobic training in a range of 30-45 minutes, working at heart rate intensity of 75-85% for a period of time before the more specific energy system work is to be done.

Typically I like to use aerobic work very early in the off-season training cycle twice per week.  In addition to the reasons I have stated above, I believe that this fundamental fitness characteristic provides safe base level training, especially for young athletes, in addition to re-introducing cardiovascular training to the more experienced player after time off from the competitive season.  I believe that 3-4 weeks of this kind of cardiovascular conditioning, placed on the appropriate days 2-3 times per week and depending on the athlete will only enhance his base fitness levels.  This in the end will provide a better foundation for the intense work and recover that is necessary for high performance sport.

The following is an example of general guidelines I use for planning the conditioning element of our off ice training program.  More specific changes to this will be done based on the individual athlete.

I hope you found this article interesting and thought provoking.  It may not be the perfect model, but it is a concept that I have used for many years with relative success.  The world of sports performance research is evolving constantly, with that I have not doubt, I could re-write this article based on the exclusive use of high intensity intervals.  The papers are there to support both views.  As a coach you have to make a choice as to what might bring about results in an efficient and safe method.  This is what has worked for me.  Feel free to debate this or ask questions on twitter @lornegoldenberg look forward to comments and questions.