Resistance and endurance training – the perfect sports conditioning partnership?

Rather like Posh and Becks, weight training and endurance training appear to be two halves of a perfect sports conditioning marriage. But, as with any good relationship, there will always be the occasional conflict and element of discord. This article examines the pitfalls for this partnership and recommends ways to maximise its harmony.

 Let’s begin with the logical assumption that weight training benefits endurance athletes, by focusing on the sport of rowing. Rowing requires an anaerobic contribution of about 30% to the 2k Olympic race distance. In consequence, rowers often train their lactic anaerobic systems with high-intensity, short duration intervals (lasting from 30 seconds to five minutes), with very short – often 1:1 – recoveries. These workouts target slow and fast-twitch muscle fibres – the latter providing much of the power needed for these turbocharged efforts.

Logic says that weight training these fibres will be beneficial, especially when you consider that the actual rowing race is completed in about six minutes, using 200-240-plus strokes – an amount of ‘repetitions’ that could easily be accrued in a standard power (70-80% of 1 repetition maximum) weight-training workout, comprising 4×10 repetitions of six exercises.

However, logic does not always apply, and this type of weight training (and indeed other types) may actually offer little direct benefit to rowers when it comes to improving their endurance. Bell and associates looked at the effects of three different weight-training programmes on 18 varsity rowers during their winter training (1). One group performed 18-22 high-velocity, low-resistance repetitions, while another did low-velocity, high-resistance repetitions (6-8 reps) and a third did no resistance training at all. All resistance exercises were rowing-specific and were performed on variable-resistance hydraulic equipment four times a week for five weeks, while the subjects continued with their normal endurance rowing training.

Which group’s rowing improved the most? When subjects were tested on a rowing ergometer the researchers found no difference between any of the groups in terms of peak power output or peak lactate levels. So the weight training apparently served no purpose. Similar findings emerged from a US study, when élite male weight-training rowers displayed no increase in VO2max by comparison with a rowing-only group, who improved their VO2max by up to 16% during pre-season training (2). So, it looks like our happy couple’s relationship is not off to a very good start!

Before we start to consider why this might be, let’s take a look at some more research from different sports. Tanaka looked at the effects of weight training on 24 experienced swimmers over 14 weeks of their competitive season(3). The swimmers were divided into two groups of 12, matched for stroke specialities and performance; one group performed weight training three days a week, alternating this with their swim workouts, while the other group did no weight training at all and just continued swimming. Both groups trained for eight weeks.

Weights – both fixed and free – were selected for their swimming specificity, with the swimmers performing three sets of 8-12 repetitions on lat pull-downs, elbow extensions, bent arm flies, dips and chin-ups. The weights were progressively increased over the duration of the training period, with a tapering period two weeks before their major competition. The result? As with the rowing studies, weight training failed to improve performance, despite the fact that swimmers who combined resistance and swim training managed to boost their strength by 25-35%.

Weight training for skiers

So are our weight-training-and-endurance couple buckling under the pressure of their ill-assorted union, while putting on a brave face and continuing to work together? It looks like divorce is on the cards, especially after a certain Mr Paavolainen’s evidence is taken into account. He and his co-workers considered the effects of weight training and other power-training methods on the performance of cross-country skiers – long considered the ultimate aerobic athletes (4).

Seven skiers performed power weight-training exercises (at high velocity against a moderate-to-high loading) as well as plyometric (jumping-type) exercises for three weeks, while another group of eight skiers performed strength-endurance high-repetition training for the legs and arms. Both groups also continued with their normal endurance training. At the end of the study period, the researchers found no difference in measures of endurance capacity, such as VO2max and anaerobic threshold, between the two groups. In short, the various weight and plyometric training sessions had not enhanced skiing performance power.

Our perfect weight-training-and-endurance couple seem doomed to disharmony and incompatibility. But could there be some mitigating circumstances? Tanaka introduced weight training into the competitive phase of his swimmers’ training cycle – perhaps not the best time. It is possible that, at this stage, the swimmers’ performances could have been impaired rather than improved by the added training load.

The relevance of maximum strength

Paavolainen’s plyometric power training cross-country skiers did increase their ability to express peak power, although this is not much use to these athletes, whose prime requirement is a highly-developed aerobic system. It may be, as exercise scientist Saziorski suggests, that since cross-country skiing is an ultra-endurance sport, weight training has little direct relevance to performance in the first place(5). Saziorski believes that maximum strength is of little importance in sports with a maximum strength requirement of less than 30%.

The rowing findings are more difficult to explain, but there is a possible answer. It is argued that when an endurance athlete reaches a certain level of performance strength – which can be developed through their everyday CV training or with weights or other resistance training – further improvements in weights-based strength will not bring about further improvements in performance. Since the rowers in the above-mentioned studies were all performing at a high level already, it could be argued that they already had more than enough ‘performance’ strength, developed through years of correctly-executed rowing technique.

 Shepard offers a very succinct explanation for why weight and endurance training can make for poor bedfellows(6). ‘Some of the most important and influential factors that result from physical conditioning occur at the cellular level in the muscles, that is, the majority of training effects are peripheral,’ he explains. ‘The number and size of mitochondria, the amount of myoglobin, the amounts of ATP and CP that are stored, and the concentrations of key enzymes associated with particular energy systems are increased. Training is specific and selective of the types of muscle fibres used. That selectivity will determine the nature of training effects and the type of performance that is improved.’

Essentially what he is saying is that training different energy systems at the same time can produce a confused physiological state – the so-called ‘interference effect’. How can pure high-power fast-twitch type IIb muscle fibre be expected to gain in size and power-generating capacity through weight training if it is being relentlessly bombarded in the same training phase – indeed the same workout – by extensive long, slow distance work or intense interval training? Training that, while bolstering its type I slow-twitch counterparts, also causes its type IIa cousins (which generate intermediate power) to defect to the slow endurance side? Depending on the training stimulus, all these muscle fibres can become orientated more towards endurance or power/speed.

So here’s the million dollar question: is there any real benefit to be gained from weight training if you are an endurance athlete? To determine this for yourself, you need to look at the specific strength requirements of your sport. If you’re a cross-country skier or marathon runner, weight training may not be relevant to improving your performance as you cannot construct a session in the gym that directly replicates what you’ll go through in a race.

However, weight training used in combination with other types of resistance training should not be discarded: marathon runners, for example, should expect to improve their performance by improving their foot strike; they can achieve this through plyometric and running drills, and specific weights exercises like the split squat and lunge. The key for them – and for similar endurance athletes – is to construct a training programme that channels their resistance-training gains into strength that will improve their technical performance.

Circuit training for endurance

Circuit resistance training (CRT) has been shown to offer a great deal to endurance athletes as it targets type I muscle fibre, can develop VO2max and lactate threshold and will also have a limited effect on increasing strength (see PP 105, June 1998). For best results, use a weight set at 50-60% of 1RM, since this seems least likely to interfere with the development of enhanced endurance capacity.

You may have noticed an apparent contradiction in that some of the studies quoted earlier did actually use CRT-style training, but to no effect in terms of improved endurance performance. This can be explained with reference to the training variables of order and recovery.

The studies by Tanaka and Paavolainen, for example, simply threw all the training ingredients together into the workout mix without taking order and recovery into account.

Taking training unit timing into consideration, Sporer et al looked at the effects of weight training on aerobic/anaerobic CV performance in 16 male collegiate athletes(7). The aim of the study was to see whether the type and intensity of aerobic training affected concurrent weight training after four, eight and 24 hours of recovery. One group performed steady state work at 70% of maximum heart rate, while the other performed 95-100% intervals with 40% MHR recoveries. Both groups were then subjected to 1RM maximum strength testing on bench press and leg press.

The researchers found that for both groups weight training gains were compromised by the endurance work unless adequate rest was allowed. More specifically, the participants’ leg muscles were negatively affected by their aerobic training in the leg press test, although bench press performance was unimpaired. In consequence, they made the following recommendations for athletes performing concurrent training:

  • If you must perform both workouts within a single day, allow at least eight hours between aerobic training and strength training;
  • Lower-body strength training should not be performed on the same day as aerobic training.

Expanding further on these suggestions, you could also consider developing strength in a specific training cycle, removed from your endurance training. This might be particularly helpful at the beginning of the training year, when you could gain most. Such a strategy could reduce the interference effect and provide the optimum conditions for developing stronger, fatigue-resistant muscles. Periodic returns to weight training micro-cycles could then be used to ‘top-up’ strength levels.

Under such conditions, Canadian researchers found that a group of rowers who strength trained for five weeks before five weeks of endurance training were rewarded by a 16% increase in VO2max and a 27% improvement in lactate tolerance(8). By contrast, rowers who trained in the reverse order boosted VO2max by only 7% and showed no improvement in lactate tolerance. The explanation? The strength-before-endurance group gained quality rowing muscle without compromise, and were able to use it to row harder and faster, with greater fatigue-resistance, during endurance training. Working out for weight training gains alone may have enabled them to push beyond their ‘normal’ previously conditioned rowing power levels.

Finally, if you are an endurance athlete you should use weight training to avoid injury, since it is almost beyond dispute that weights and resistance training exercises can protect against injury by strengthening soft tissue.

John Shepherd


  1. Journal of Sports Sciences, 7 pp205-214, 1993
  2. Medicine and Science in Sports and Exercise, vol 26 (5) p575 1994
  3. Medicine and Science in Sports and Exercise, 25, pp952-959 1993
  4. European Journal of Applied Physiology, 62, pp251-255 1991
  5. In Dick F – Sports Training Principles, p238, A and C Black, 4th edition, 2002
  6. Canadian Journal of Applied Sport Sciences 3, pp9-15 1978
  7. Journal of Strength and Conditioning Research 17 (4) pp638-644 2003
  8. Canadian Journal of Applied Sport Science vol 13:4 pp214-219 1988
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