A topic that has always been of interest to me is concurrent training. By definition, concurrent training is a training cycle where by both strength as well as endurance exercise is performed within the same training cycle. This is inevitable within both individual as well as team sports, but also popular with the everyday punter who knows it is important to be both fit as well as strong. The question is though, as an athlete or as a coach, how do you get the most out of your training cycle and be the most prepared for your sport? Within the blog, I am going to dive deep into the science behind the adaptations different intensity levels of both strength training as well as endurance training have on our body. I am also going to provide practical advice on how to structure your training blocks and your individual work outs so you can mitigate the interference effects and improve your adaptations over time.
Firstly, let’s take a look at what we are up against when going down the pathway of concurrent training:
Long duration cardiovascular training has the following negative effects on strength training:
-Reduces motor unit recruitment and rapid voluntary neural activation.
-Depletes muscle glycogen stores.
-Skeletal muscle fibre type transition from 2B to 2A and from 2A to 1.
-Potential overtraining through a lack of recovery process when compared to training time.
-Decreased muscle cross sectional area and in the rate of muscle force production.
(Garcia-Pallares & Izquierdo, 2011).
What are the adaptations we make to strength training?
Local muscle endurance (LME) is targeted through moderate to high loading, high volume strength work comprising of sets of 6 to 12 repetitions whilst maximal strength and power (SPT) is targeted through high loading, multi set protocols of 1 to 6 repetitions per set. Maximal strength and power training induces central adaptations such as: improved neural firing rates and changes to synchronisation, higher threshold motor unit recruitment, decreased co-contraction of antagonist muscle groups and lower metabolic demands at the muscle level. LME style training induces changes at more of a peripheral level, including: increases in contractile protein synthesis and subsequent increases in fibre size and cross sectional area, increase in glycolytic enzyme content, declines in capillary and mitochondrial density as well as an increase in metabolic and hormonal stress at a cellular level (Garcia-Pallares & Izquierdo, 2011).
What adaptations come from cardiovascular training?
Training for maximal aerobic power (MAP) and to subsequently increase VO2 max consists of higher intensity workloads (85% of VO2 max and above) and evokes adaptations at a peripheral level. These changes are seen as: increases in muscle glycogen stores, increases in capillary and mitochondrial density and increased oxidative enzymes. In contrast, the adaptations seen when employing a lower to moderate intensity style of cardiovascular training (75 to 85% VO2 max) are as follows: central adaptations seen through improvements in pulmonary diffusion and haemoglobin affinity, increases in blood volume as well as increased cardiac output (Garcia-Pallares & Izquierdo, 2011).
What is the interference effect?
It is important to train with the understanding of the interference effect which unfortunately sees the body trying to make adaptations which compete with one another. Not only do certain stimuli from both strength and cardiovascular training interfere with one another at an adaptation level, they can also produce high levels of fatigue which make it inevitable that over training will occur. The following recommendations are advised: Training for LME (hypertrophy) as well as MAP (VO2 max) simultaneously would see competing peripheral adaptations take place, especially regarding the capillary and mitochondrial densities within the skeletal muscle. To decrease the interference effect whilst training for LME, it is proposed that a lower intensity approach to cardiovascular training be utilised, as these adaptations are central and involve the cardiac musculature. This approach holds true when training for SPT also, as the central adaptations taking place within the neuromuscular system will not be interfered with as the adaptations take place within the central, cardiac musculature. This doesn’t mean that you cannot train for increased MAP though, but if doing so, remember to train your strength session’s with an intensity focus, so as to not interfere with the adaptations at the peripheral muscle level (Garcia-Pallares & Izquierdo, 2011).
How do you get the most out of your sessions and control fatigue levels?
In order to maximise your adaptations whilst preventing an over training or underachieving phenomenon whilst concurrently training, it is proposed that training should be scheduled in a block periodisation model encompassing no more than 2 variables at once and lasting roughly 5 weeks in duration. It is important to schedule the training as effectively as possible, with at least 8 hours of duration between each session. This helps to reduce fatigue and increase recovery of the previous session and mitigate the interference effect. When choosing the 2 goals for each training block, remember the above mentioned recommendations and think along the lines of reducing interference. For example, the goal of hypertrophy would accompany the goal of increasing cardiovascular endurance, as hypertrophy is a peripheral muscle stimuli, and cardiovascular endurance is a central cardiac stimuli. In another training block, the opposite approach could be taken where by the SPT goal would be accompanied by an increase in MAP, as the strength training is a central neuromuscular adaptation and the MAP is a peripheral muscle adaptation, again 2 stimulus which do not conflict. A huge and often overlooked factor when programming strength training sessions is the number of repetitions per set as well as the chosen intensity level of each repetition range. Due to the risks of overtraining, intensity should be prescribed as between 50 and 85% of a given total capacity per set. This means always leaving repetitions in reserve, and placing a larger emphasis on session quality and the ability to recover, than the perceived exertion level per session. It is recommended to prescribe 3 to 5 working sets across 4 to 6 exercises within a given strength session. When programming a concurrent training block, no more than 3 strength sessions per week is advisable in order to maintain quality and recoverability of a given session (Garcia-Pallares & Izquierdo, 2011).
References:
Garcia-Pallares, J., & Izquierdo, M. (2011). Strategies to optimpize concurrent training of strength and aerobic fitness for rowing and canoeing. Sports Medicine, 41(4), 329-343.