The importance of strength cycles for endurance athletes:
Why you should spend a month 'lifting things up and putting them down'.

Alan Couzens, MS (Sports Science)

Dec 4th, 2014

It’s that time of year again for our Endurance Corner athletes – the annual “Big Steel Challenge”. The mission is simple: Move as much weight as you can from Dec 1 – 31. That’s it. No hard and fast rules beyond that.

By necessity, most athletes wind up gravitating towards exercise that are:

In a future article, I’ll get into the ’how’ in a little more depth, but for now, I want to address that persistent question of Why? Or, more specifically, why should athletes whose event lasts 8+hrs at a very modest force output (something in the vicinity of doing short range step ups with 3lb dumbells in hand) want to start pushing non-specific heavy loads around?

The answer to the above can be found in very strange paradox that we see every year – despite spending a lot of time doing the equivalent of 3lb partial rep step ups, the guys who do well in Ironman are traditionally STRONG. Last year, Justin put up 90 Tonnes over the month (you can read more about his take on Big Steel here) – a monthly training load comparable to that of athletes from the traditional strength sports!

Justin wasn’t alone as an outlier here. In fact, across the years that we’ve done ‘Big Steel’ there has been a strong relationship between athletes who are fast (in an Ironman sense) and athletes who can put up a lot of poundage.

I’ve talked a little about the reasons for this relationship in previous articles but to put it in its simplest terms, “muscle moves stuff”. If you want to move stuff at a good rate, whether that stuff is your bodyweight, a bike or a barbell, there is a certain amount of muscle required for the task. Even exceptionally well trained muscle has its limits in how much aerobic work it can accomplish – something in the range of 180ml/kg (Beekley et al., 2006) or, in power output terms, ~15W/kg of active muscle mass.

So, the million dollar question becomes, is endurance work alone sufficient to maintain this muscle mass? The answer is a definitive NO. The bulk of studies that have looked at changes in fiber size with endurance training have actually found a decrease in muscle fiber size with endurance training without complementary strength work. For example, Kraemer et al. (1995) found an ~20% reduction in muscle fiber size across all of the fiber types with an endurance only protocol. This study was performed on young men. If we factor in the natural muscle loss that occurs with age on top of this, the year to year reduction in muscle mass, over periods of long term endurance training, is even more significant.

In the short term, a reduction in muscle fiber size represents a great deal for the body looking to enhance endurance performance as quickly as possible. Your body approaches the problem with a double whammy solution…

  1. I’ll increase mitochondria and capillary density so that I can get more O2 to the muscle
  2. I’ll decrease the size of the muscle so that I can flood the muscle with O2 more quickly.

This reduction in muscle fiber size, while representing a great deal for short term adaptation, may, in the long term, be the athlete’s greatest limiter!

Remembering that, for even very well trained muscle (~180ml/kg/min), an athlete will still require close to 30kgs of appendicular mass to put up competitive Ironman numbers. While this muscle must (of course) be of very high aerobic quality, having enough plain old muscle is step 1!

This extends beyond training theory…

In my last post, I outlined a number that sums up an athlete’s training response. The higher the number, the better an athlete responds to a given training load. Unsurprisingly, I’ve observed a very close relationship between this number and the body type/muscle mass of a given athlete in my own training squad. This is most obvious when I compare against an athlete’s DEXA data that shows actual muscle mass, but even plotting against a less sensitive indicator, like Body Mass Index, the relationship between an athlete’s rate of improvement and the amount of muscle that they have to work with is obvious.

Athletes with more muscle ‘reserve’ to work with are less likely to plateau &, overall, respond better to training.

Of some interest is the way the data spreads out at the high BMI rates, I’d suggest that this spread tracks closely with the girth spread of these high BMI athletes :-), i.e. the difference between a ‘muscle heavy’ vs a ‘fat heavy’ athlete. However, it’s worth noting that, even for athletes who might be a little 'pudgy', they still tend to put up a higher training response than athletes who are on the ‘too skinny’ side of the chart. Put more bluntly, don’t be too afraid to gain a little weight (of any description) when you are looking to build some reserve in the early season.

I'm not the first to note this relationship between training response and muscle mass. Chaouachi et al. (2005) observed almost double the training response to a given training load when comparing mesomorphs (moderate-high muscled athletes, Mean BMI=23.5) with ectomorphs (low muscle athletes, Mean BMI=19.2).

So, all of the above is a long way of saying that endurance sports are catabolic by nature and, in the absence of sufficient strength work, your performance reserve will be, year after year, whittled away. For both your long term development as an athlete, & your long term functionality as a human being, I’m not sure there is a better way to spend a month than with a simple focus on picking things up and putting them down.

Train smart,




Don't miss a post! Sign up for my mailing list to get notified of all new content.

Name:  Email:
Topics you're most interested in? (optional)

Have no fear - I won't spam you or sell your info.