Concurrent Strength and Endurance Training

Abstract

Concurrent strength and endurance training appears to inhibit strength development when compared with strength training alone. Our understanding of the nature of this inhibition and the mechanisms responsible for it is limited at present. This is due to the difficulties associated with comparing results of studies which differ markedly in a number of design factors, including the mode, frequency, duration and intensity of training, training history of participants, scheduling of training sessions and dependent variable selection. Despite these difficulties, both chronic and acute hypotheses have been proposed to explain the phenomenon of strength inhibition during concurrent training. The chronic hypothesis contends that skeletal muscle cannot adapt metabolically or morphologically to both strength and endurance training simultaneously. This is because many adaptations at the muscle level observed in response to strength training are different from those observed after endurance training. The observation that changes in muscle fibre type and size after concurrent training are different from those observed after strength training provide some support for the chronic hypothesis. The acute hypothesis contends that residual fatigue from the endurance component of concurrent training compromises the ability to develop tension during the strength element of concurrent training. It is proposed that repeated acute reductions in the quality of strength training sessions then lead to a reduction in strength development over time. Peripheral fatigue factors such as muscle damage and glycogen depletion have been implicated as possible fatigue mechanisms associated with the acute hypothesis. Further systematic research is necessary to quantify the inhibitory effects of concurrent training on strength development and to identify different training approaches that may overcome any negative effects of concurrent training.

Endurance and neuromuscular changes in world-class level kayakers during a periodized training cycle

“…strength training objective at P1) and maximal aerobic power (i.e. endurance training objective at P2), because these are thought to be two modes of training that lead to opposite physiological adaptations at the peripheral level that prevent the body from optimally and simultaneously adapting to both of them (Leveritt et al 1999). Thus, while hypertrophy training would be attempting to increase contractile protein synthesis in the muscle, causing considerable metabolic and hormonal stress at the cellular level, training for aerobic power would require the muscle to increase its oxidative capacity (Docherty and Sporer 2000;Sale et al 1990a).…”

“…One important aspect was controlling for training volume and, especially, limiting the frequency of resistance training to only three sessions per week because, as already addressed in the introduction, higher frequencies have proved to compromise strength gains in most concurrent training studies. Research has also highlighted the importance of the order and timing of the aerobic and strength training sessions in order to minimize possible interference effects (Leveritt et al 1999(Leveritt et al , 2000Sale et al 1990b;Sporer and Wenger 2003). Thus, insufficient recovery between training sessions might limit simultaneous adaptations to strength and endurance training.…”

“…However, results of subsequent research have been equivocal, with studies both supporting (Bell et al 2000;Craig et al 1991;Dudley and Djamil 1985;Hennessy and Watson 1994;Kraemer et al 1995) and questioning (Häkkinen et al 2003;Hunter et al 1987;McCarthy et al 1995McCarthy et al , 2002Sale et al 1990a) the universal nature of such interference. Several factors such as initial training status of the subjects, exercise mode, volume, intensity and frequency of training, scheduling of sessions, and dependent variable selection may influence the level of interference and explain the contradictory results of these studies (Docherty and Sporer 2000;Leveritt et al 1999;Sale et al 1990a). A detailed examination of the existing research on this topic seems to indicate that the volume, especially the frequency of training, may play a critical role in the adaptations consequent to concurrent training (Häkkinen et al 2003;Izquierdo et al 2005;McCarthy et al 2002).…”

“…Unfortunately, there are very few studies in the scientific literature that have explored the effects of periodized training on sports with great demands of both strength and endurance, and even fewer that have done so using elite athletes as subjects. Based on evidence from existing research (Docherty and Sporer 2000;Leveritt et al 1999Leveritt et al , 2000Sale et al 1990b;Sporer and Wenger 2003), we chose to structure a periodized program aimed at minimizing the possible interference effects in the simultaneous training of the strength and endurance components of physical fitness. Therefore, it was the purpose of the present study to examine the effects brought about by a 12-week periodized program of combined strength and endurance training on selected neuromuscular and cardiovascular parameters in a group of world-class level kayakers.…”

Concurrent training effect on muscle fibers in Wistar rats

“…Robert C. Hickson (1980) was the first author to describe this procedure and a number of investigations into the effects of this form of training have since been conducted. Reviews of the literature carried out by Leveritt, Abernethy, Barry, and Logan (1999), and Paulo, Souza, Laurentino, Ugrinowitsch, and Tricoli (2005) reported that some authors state that the combination of the two training methods in a single session may have a considerable structural and metabolic impact on muscle fibers, resulting in the loss of contractile force and physical capacity (Hickson, 1980). According to Baar (2006), however, little was known in the 1980s regarding the effects concurrent training on physical fitness, the increase in muscle mass and mitochondrial density.…”