My favorite TV channel of late is, without question, Universal Sports. Prior to the introduction of this channel, we rarely saw swimming and triathlon outside of major events like the Olympics. Now, with 24 hours of air time to fill, we get to see all of the ITU world cup races, the world athletics circuit and small invitational swim meets.

Because of this, we also get to see superstars racing at far below their best. When this occurs, we hear comments like, “Phelps is coming off a tough training block right now.” But what does that mean? What does a “block” of training consist of and why is the block approach preferable to constant load over the season? Is there an optimal duration for each training block? I’m going to delve into these questions a little…

Our bodies are remarkable time pieces. Think about it, at any given time, a large portion of the way we feel is related to where we are within our circadian (daily) and circamensal (monthly) cycles. Within the circadian cycle, sports performance is consistently best in the late afternoon, a time coinciding with the top of the sine wave — peak body temperature and catecholamine response. Following this work peak the body goes into repair mode where it shuts down the capacity for work in favor of recovery. Even if we didn’t use all of our work capacity in the peak phase, the recovery cycle (sleep) remains. The same is true over the monthly cycle.

Many cycles of remodeling and repair occur within the body over the period of approximately four to six weeks. Those who’ve been unfortunate enough to fall from the tree house at some point in their youth are more than familiar with this four-to-six-week period of immobility while the osteoclasts do their clean up duty and the osteoblasts lay down new bone to ensure that repair and remodeling occurs. It’s worth considering that even when the loads that cause the injury are significantly different, such as multiple fractures from falling 20 feet from the top of your tree house to tiny stress fractures caused by training, the period of repair, remodeling and consequent immobility is relatively constant (four to six weeks). This has direct carry over to any “injury” we may present to the body, including training.

Just like the cycles witnessed in bone repair, muscles undergo a similar repair process in response to load — a clean up phase that goes on between days 3 and 14 post training and a repair and remodeling phase that occurs five to 35 days post training event(Duguez et al 2002). This can be illustrated as follows:

The above diagram shows a typical performance response to a “dose” of one 100TSS session (a typical 90-minute to two-hour training session). The body experiences a minor beat down, during which performance is compromised, followed by a remodel and repair phase that ends with the muscle being stronger and more ready to deal with significantly more load 21 days later.

So, what happens if we significantly increase that load to say 100TSS every day for three weeks? What does it do to the cycle? The answer is, perhaps surprisingly, very little. Following the three week beat down, the body is again completely supercompensated three weeks post despite significantly more abuse and a much greater performance bump:

Of course, in the interests of fitting enough load in you may not wait for full compensation to occur. Even allowing seven to 14 days post load will place the athletes performance potential above where it was pre-load. However, the practical point is that it is not the extent of the load that determines the body’s cycle of repair. Or, put a little more bluntly, if the athlete only accomplishes 50% of the target load for the loading portion of the block, it doesn’t mean that you should omit the recovery portion or abandon the structure of the training block. The integrity of the block structure is paramount to ensuring the balance of training and recovery occurs, even when the training is not significantly injurious.

This point becomes especially pertinent when dealing with busy age group triathletes. It is all too common to have “things crop up” that compromise the magnitude of beat down they are able to inflict on themselves during the loading portion of a block. The follow up comment is generally, “But I’m not feeling too tired, can’t we just ‘keep it rolling’?” or worse still, “Can we play catch up on the load that was missed in the prior block?” Sorry, your body doesn’t work that way. Athletes who attempt to “keep it rolling” too long consistently wind up running out of mojo and getting less performance from their load. To get the most from any load that you are able to place on your body (whether limited by physiology or schedule) requires getting “in sync” with your natural body cycles and unloading after each block.

Train Smart