Weight Training for Endurance Athletes
Disclaimer: These opinions are based on anecdote (my own experiences) and not research data, and therefore may well not be applicable to anyone else.
There seems to be a bit of debate about whether weight training is of any use to athletes like triathletes or cyclists at all. Certainly, the sports science literature is not unequivocal that it is a good thing: there is evidence that whilst weight training increases strength it does not, for example, increase cycling power (1). Maximum power or VO2Max (the athlete's maximal use of oxygen) rather than leg strength are the relevant factors for a cyclist aiming to ride a timetrial quickly (2). Amongst athletes themselves, many worry that weight training in the gym will cause a build-up of muscle making them look like Arnold Schwarzenegger and the increased body weight will result in slower times. But is this true? And if not, will it make you faster? Do the benefits of weight training (if any) adequately compensate for the excruciating boredom of the weight room?
Physiology of the Athlete
My own view is that weight training is useful to at least some triathletes, including myself, but may not be appropriate for all. I am what is technically called an extreme ectomorph, and popularly a scrawny bastard. As such, I naturally have a low body weight (at age 32, height 5 ft 11",weight 10 st 10 lbs-150 lbs/68 kg) and body fat (measured, slightly unconvincingly I admit, at 5.1% before the Boston Marathon in 1998!). My weight is very stable whatever I eat and it is only when I'm doing weights and have gained a couple of pounds that I actually manage to make it out of the "underweight" category into "normal" on those crap "ideal weight" charts that one sees in magazines. At least for someone like me then, the idea that weight training causes a massive general hypertrophy of muscle leading to a major increase in body weight is exposed as a myth (3). I find I am a couple of pounds heavier than I would be if I stopped weight training and switched to watching videos and eating ice cream, but that's it. However, I do get stronger, as measured by the amount of weight I can lift. This can be a very large increase in strength: 2 to 3-fold on some exercises, over long periods.
This may not be true for others, and is something to be considered. More mesomorphic individuals may indeed find that excessive time in the weight room causes their body weight to rise too high; I wouldn't know.
I follow a simple programme, which I vary slightly from year-to-year, partly to avoid getting "stale", and partly to experiment with other things such as different exercises. Currently using Nautilus machines, but have also used other types of machine and also free weights. I don't think it matters really: they all work. I do a general conditioning programme of about a dozen exercises; at the moment these are: Bench Press, Leg Extension, Lateral Pulldown, Leg Curl, Overhead Press, Calf Raises, Triceps Extension, Hack Squat, Leg Adduction, Leg Abduction (1 set each on these last three to take up one exercise "slot" in my programme), Lower Back Extension, Preacher (Bicep) Curls, Abdominal Crunch, Forearm. Most exercises I do three sets of 12 repetitions, working to failure between 8 and 12 reps on the final set, and raising the weight when I can do three sets of 12. Working to failure is essential to increase strength; no adaptations are stimulated by a workout which is already within the capabilities of the athlete. (This is why women doing lots of ultra-low-weight reps with no visible effort are wasting their time.)
Some coaches recommend "compound" exercises for endurance athletes as they feel these more closely mimic the movements of the sports themselves. (Compound exercises are ones that use groups of muscles to effect their movement rather than isolate individual muscles; examples include the Compound Row or the Super Pullover). This may be true, but I feel that in my case I do not benefit from compound exercises as I get to a level defined by the weakest muscle in the group and then improve no further. For example, in the compound row I am limited by the "grip" in my forearms, so swimming muscles such as lats and shoulders are not significantly worked for me on this exercise. This is incidentally why I do the forearm exercise, even though it might seem entirely superfluous for a triathlete: I have markedly improved at the lateral pulldown for example, a real swimmer's exercise, since starting to do this one as the limiting factor is now the latissimus dorsi (which is the point of the exercise) and not the muscles of the forearm responsible for maintaining a grip on the bar.
Received wisdom is that a low number of reps builds strength and a higher number (e.g. 20-24) builds endurance. I am not sure of any real evidence for this though, and really there is not much difference between 12 and 20 reps anyway. If anything, I incline towards a few more reps of slightly lower weight, as I find this makes it easier to maintain a good form when performing the exercise, which makes the exercise more beneficial, and also avoids the risk of injury that lifting very heavy weights involves. If the weight is heavy enough though, those last few reps are even more excruciating than in a high weight/low rep programme!
At some point I reach a plateau which seems to be as strong as I can get at that exercise. At this point, I am switching to doing one set of 20-24 reps of about 10% less than the peak weight I reached to maintain the strength gains achieved. At the end of the winter, all exercises should be on this "1x20-24" maintenance programme, and then during the racing season I will only visit the weights room once/week. This should hopefully allow maintenance of strength throughout the season without taking up too much training time-one workout of about 45 minutes to an hour every week. My naturally-low body weight means that for me some weights are essential throughout the year to maintain strength as I can lose strength very quickly: I lost loads in the weeks off during our Manali-Leh cycle ride.
Frequency of Training
Excessive time in the weight room obviously gets in the way of "proper" training running, cycling or swimming. In addition, weight work is very demanding and takes time to recover from. This may be where the myth of loss of speed from the weight room arose: It's hard to go fast the day after a tough weights session as the muscles are still recovering, and this is probably why most people do their serious weight training in the off-season from their sport. I find that the optimum for me is two days off between weights sessions when I'm in a build phase: every other day is just too frequent and fatigue builds up and I stop improving if I try and train every other day. This means I cannot weight train three times/week as recommended in many weight training programmes and so typically weight train twice/week.
Benefits of Weight Training
In untrained individuals, there is some evidence that weight training can improve performance in endurance sports such as cycling (4), but this does not seem to apply to trained individuals such as athletes. However, simply because power is not increased, or increased leg strength does not necessarily correspond to increased speed, does not mean there are no benefits to weight training for endurance athletes. There are several:
Avoidance of Injury. Weight training also strengthens ligaments and tendons as well as muscles. This greater overall strength in the system makes one less likely to suffer from overuse injuries. A body strong from a good winter weights programme is much more able to handle the demands of a tough training and racing season, such as preparing for a marathon or Ironman. In my experience, this is not a nebulous "reason to justify weights because I want to do them anyway" benefit, but a real plus. In the longer term, it actually contributes to speed as well, since an uninjured and non-injury-prone athlete can train more frequently and harder with more speedwork than one who is constantly having to nurse an injury. A stronger person is also more likely to come out of injuries from things such as bike crashes better off than a weaker person as well.
Anecdote: Way back in 1993 (pre-weight training (: ) I badly tore my calf muscle and was left with scar tissue in the leg that I could always feel when running. I later discovered that strengthening the muscle with calf raises stopped it causing trouble and in fact have not even been able to feel the scarring for several years now.
Balance of Fitness. A complete-body weights programme will help to "balance-up" an athlete's fitness. Runners, for example, usually have poor upper body strength since they are mainly using their legs in their sport, and weight training can compensate for this. I remember one occasion the day after a half marathon where a friend complained of his arms hurting! He just ran, and his upper body was trashed from the long distance, even though it wasn't doing the bulk of the work. This fatigue probably led to bad running form later in the race and concomitant reduction in efficiency and/or speed. Cyclists can have some of the same problems; for example when climbing out of the saddle or sprinting, strong arms and body core are vital to transfer energy efficiently. (If you don't believe me, try and ride standing up no handed to mimic weak arms and body: even if you don't crash [!] you can't do it because you need to be solidly fixed to the bike with minimal movement so that energy transferred through your body all goes out through the drivetrain). It is hard to train these muscles on the bike, but a spot of weights sorts it out very quickly, no problem.
Bone Density. Both males and females as they age tend to lose minerals from the bones, lowering their density and weakening them. This loss of bone density can be worse in endurance athletes than in sedentary individuals, especially those whose sports are non-weight-bearing such as cyclists and swimmers (5, 6). However, weight training has been shown to prevent this reduction in bone density (7,8).
You Do Get Faster! Despite the evidence arguing against a direct correlation between weight training and measurable parameters affecting endurance sports performance, my own experience suggests otherwise. Although I would accept that there are obviously many variables playing a part, notably the length of time I have been running/cycling or whatever, and an improvement in my training over the years, I have found that the most direct correlation between performance and a training factor for me is strength; see the table below:
Unfortunately I do not have a standard performance (e.g. 10 km road race or 10 mile TT) for each year to compare with each other (sorry, it's more fun trying different things!), but I think the general trend is pretty clear. The trend with other training is harder to see or non-existent: I have never trained with a heart-rate monitor, have not had access to a running track for measured intervals after 1998, trained less 1999-2001 than 1997-1998, etc...
(1) Rutherford et al. (1986) J. Sports Sci. 4 101-7.
(2) Bentley et al. (1998) J. Sports Med. Phys. 38 201-7.
(3) Hickson et al. (1988) J. Appl. Physiol. 65 2285-90.
(4) Marcinik et al. (1991) Med. Sci. Sports Exerc. 23 739-43.
(5) Bennell et al. (1996) Br. J. Sports Med. 70 205-8.
(6) Stewart & Hannon (2000) Med. Sci. Sports Exerc. 32 1373-7.
(7) Tsuzuku et al. (1998) Calcif. Tissue Int. 63 283-6.
(8) Sinaki (1996) Curr. Opin. Rheumatol. 8 76-83.