Introduction

Resistance training refers to a type of training in which practitioners train against resistance, such as by lifting, pushing, or holding a weight. Muscular resistance exercises usually consist of one or multiple sets of repetitions spaced by resting time using the same or different resistance. Although one set requires less time to be executed than multiple sets, performing multiple sets results in greater strength and hypertrophy.^[19][29] Fitness enthusiasts and researchers have created several multi-set training systems, such as circuits, drop and strip, superset, and pyramidal training. A ubiquitous recommendation from the domain reference institution, the American College of Sports Medicine (ACSM), is to perform two to three sets with eight to 12 repetitions.^[38] The present research refers to such a style of training as traditional training. Traditional training varies according to athlete level and trainability, such as age and previous training experience. In particular, regular variation of the training program, such as changing the training method or volume, is necessary to maintain progression.^[30] This is because varying the training method maximizes gains by bringing novelty into the trainer’s routine. Regarding age, experts recommend tailoring the physical activity to the subject’s limitations and chronic conditions.^[27] Having several resistance training methods to draw on allows the routine to be adapted to the practitioner’s physical condition and avoids a plateau in progression.

The pyramidal system of training refers to methods in which sets are performed with increasing (or decreasing) weights and repetitions, in such a way that the number of repetitions is low when the weight is high (and vice versa).

In this article, we conduct a narrative review of the pyramidal method. Section I presents the physiological adaptations to pyramidal training, while Section II draws comparisons of different pyramidal systems. The discussion and conclusion are presented in Section III.

Physiological Adaptation to Pyramidal Resistance Training

The body’s adaptation to pyramidal and general resistance training occurs in many systems, including the cardiovascular, endocrine, nervous, and immune systems. An introduction to this topic can be found in Mazzeo,^[22] and an exhaustive literature review is presented in Fleck et al.^[13] and Reiss et al.^[31] The following sections describe these adaptations.

Anaerobic Adaptations

Resistance training usually involves short and intense bouts of exercise (<2 mins), and, therefore, relies heavily on the anaerobic pathway for energy production. Energy is produced through the degradation of creatine phosphate and glucose into ATP without the need for oxygen. These reactions are fast compared with the aerobic pathway, though they deliver significantly less energy. Resistance training results in the augmentation of the creatine, glycogen, and ATP concentration, leading to an improved anaerobic pathway.^[31]

Aerobic Adaptations

The mitochondria are micro-organisms that are present in the body’s cells. They are responsible for the conversion of glucose and fat into ATP using oxygen. In general, training increases the number of mitochondria inside the muscular cells, which results in a higher proportion of energy expenditure from the aerobic pathway during exercise, thereby sparing muscle glycogen and creatine reserve. This effect is sustained by the redirection of blood flow to the working muscles while exercising, which, supported by an improved cardiac output function, ensures the continued delivery of oxygen, liver glycogen, and fat.

Although the improvement in fat metabolism and the aerobic pathway is less pronounced in resistance versus endurance training, it is known that resistance training enhances local muscle endurance.^[13] This results in an increased ability to perform repetitions during a set, which in turn produces higher hypertrophy and strength, as these training outcomes tend to increase as a function of the training volume. A similar effect is also obtained through creatine supplementation.^[18]

Pyramidal methods likely enhance aerobic filial, thereby enhancing local endurance more so compared with traditional training, as first sets are performed with less weight, which allows for more repetitions to be performed.

Neural Adaptations

The expected effect of the pyramidal method and general resistance training is an increase in strength due to neural and muscular adaptation. Neural adaptations occur first in beginners, causing changes in the motor unit firing pattern.^[14] In practice, this means that strength depends on the number of myofibers that motor units can recruit to perform a movement while releasing antagonist muscle and protecting joints.

Muscular Adaptations

High-intensity training, such as training to failure, causes micro myofiber lesions, which results in soreness and muscle catabolism. Biomarkers of catabolism along with muscle asphyxia resulting in lactic acid trigger a retro-action loop, leading to an increase in myofiber size (hypertrophy) and—to a lesser extent—an increase in their number (hyperplasia). Detraining results in hypotrophy but not hypoplasia. That is, newly created myofibers likely do not disappear with detraining.^[5]

Resistance training also changes muscle composition by stimulating type IIA and type IIX myofibers. Both allow for quick force production and muscle contraction but are less resistant to fatigue compared with type I fibers, which are typically associated with endurance. However, type IIA fibers incorporate more mitochondria and, therefore, are more resistant to fatigue than type IIX fibers. Hypertrophy applies to all fiber types, although type I fibers are impacted to a lesser extent.

Endocrinal Adaptations

Blood occlusion through asphyxia during exercise likely contributes to hypertrophy. Blood occlusion inhibits myostatin, which is known to play a role in cachexia. Although pyramidal training is suspected of impacting microvascular oxygenation during exercise, recent findings suggest that microvascular oxygenation is similar in pyramidal and traditional training.^[2] In general, there is no consensus on the role of hormones in muscular hypertrophy.^[31] For example, although testosterone is a very well-known anabolic hormone, the testosterone level in elite athletes is lower than the reference range for non-elite men. Further, powerlifters have a lower testosterone level on average compared with levels recorded in other sports, such as skiing or basketball.^[35] These surprising findings suggest that it is rather the sensitivity threshold to testosterone that increases in training.

Cardiovascular Adaptations

Although resistance training is not a type of cardiovascular training, the compression of blood vessels along with the Valsalva maneuver produces extreme heart pressure.^[21] This response is attenuated in trained athletes during exercises.^[12] The impact of resistance training on cardiovascular function was outlined in recent studies, with positive effects on blood pressure noted at rest,^[11] although the underlying mechanisms for this remain under investigation.^[23] Ghanbari-Niaki et al.^[15] found that the pyramidal method specifically reduced blood viscosity, thereby diminishing cardiovascular risk factors.

Despite these positive effects, there is an increase in aortic stiffness when performing high-intensity resistance training.^[4][8][25] Aortic stiffness is associated with lower muscular strength^[7] and is an established risk factor for cardiovascular morbidity. The mechanisms that underlie the loss of aortic compliance following strength training are not clear,^[36] though this can be compensated for by adding an aerobic component to the training.^[6][17] In this respect, the effects of pyramidal training on aortic compliance deserve further investigation, particularly because of its impact on endurance, that is aerobic training.

Classification of Pyramidal Training Systems

There are at least four pyramidal systems, which are defined as follows:

• Half-triangle pyramid:
  • Heavy-to-light (HL): the practitioner decreases the weight between sets while increasing the number of repetitions.
  • Light-to-Heavy (LH): the practitioner increases the weight between sets while decreasing the number of repetitions.
• Triangle pyramid: a combination of HL and LH protocols, as follows:
  • Double progressive system or reversed pyramid (RP): a combination of an HL pyramid followed by an LH pyramid, except that only the number of repetitions increases in the first phase while the weight remains the same.
  • Symmetric pyramid (SYM): a combination of an LH pyramid followed by an HL pyramid in which sets from the LH phase are applied in reverse order in the HL phase.
  • Asymmetric or diagonal pyramid (ASYM): similar to SYM pyramid, except the number, weight, and repetition number of sets differ between the first and second phases.

Examples of pyramidal training protocols are described in Table 1.

Training Volume of Pyramidal Methods

Training volume refers to the amount of work (in joules) performed during a given period, such as one training session or one week. For example, an exercise performed once a week, consisting of 10 squats at 100 kg results in 1,000 N/week. Assuming that the vertical distance traveled by the weight during the exercise is around 1.5 m, then the resulting amount of work is equal to 1,500 J/week.

There is a clear relationship between training volume and outcomes, such as strength, power, decrease in body fat, and motor performance. It has been suggested that the training volume is more important than the training frequency and number of sets in terms of strength gains.^[13] A recent meta-analysis^[34] demonstrated that an increase in resistance training volume produced higher hypertrophy and concluded a dose-dependent effect. The same conclusion has also been applied to endurance training,^[28] although this is more controversial.^[10] In Costill et al.,^[10] it was shown that swimmers who trained 3 h per day did not improve their performance compared with swimmers who trained only 1.5 h per day. However, it could be that the test was not adapted to the training provided, or swimmers from the first group were overtrained. In sum, all training outcomes are dose-dependent on training volume unless the training volume exceeds athletes’ capacity to rest and compensate.

Table 1 illustrates the training volume across the different types of pyramidal training.

Comparison of Pyramidal Training Systems

Training with heavy or light weights results in different muscular adaptations: endurance, strength, hypertrophy, or power. Therefore, pyramidal training is a priori a very complete method of producing all these adaptations within a single exercise compared with traditional training. Having said that, there are significant differences between different pyramidal systems.

Comparison with Traditional Training

Evidence suggests that half-triangle pyramids and traditional training are equivalent in terms of strength gains and muscle hypertrophy. Angleri et al.^[3] conducted a randomized intra-subject study over 12 weeks of leg training. Participants trained one leg with traditional training and the other leg using the drop-set or crescent pyramid system. The study showed that crescent pyramid and drop-set systems did not result in a significant increase in the one maximal repetition (RM) or muscle cross-section area compared with traditional training. All subjects in the study were already well trained. However, interestingly, the same results were observed in another population. In an eight-week full-body training randomized crossover,^[32] the authors showed that decrescent pyramidal and traditional training similarly impacted muscular strength and hypertrophy in older women (training and detraining). However, the impact of contraction types (eccentric, concentric, plyometric, or isometric) was not discussed in these studies.

For a practitioner willing to spare time, half-triangle pyramids have a lower workload than traditional training or triangle pyramids (Table 1). In fact, by working at a higher intensity, pyramidal methods recruit an increased number of fast-moving motor units, which compensated for the loss of training volume. Triangle pyramids have the same or a slightly higher training volume than traditional training. However, the number of repetitions performed at low intensity and high frequency is higher in triangle pyramids than in traditional or half-pyramidal training. That is, a greater endurance outcome can be expected in triangle pyramids versus traditional training.

In contrast, Costa et al.^[9] showed that pyramidal training led to a decrease in performance in the lower (but not the upper) limbs of the body during a training session. Compared with traditional training, this suggests that pyramidal training leads to more rapid failure, leading to reduced training volume and increased rest between sessions. Although this finding should be approached with caution, it suggests that pyramidal methods offer fewer benefits compared with traditional methods of resistance training.

Comparison between HL and LH Protocols

In Leighton et al.,^[20] a study that is also reported in Fleck et al.,^[13] the effectiveness of eight different protocols was evaluated by comparing isometric strength outcomes. In particular, the authors compared the HL (Oxford) and LH (Delorme) protocols and found that HL produced better outcomes in elbow extension and the back and leg, while HL produced higher strength outcomes in elbow flexion. This suggests that the two methods may have different impacts on the upper or lower limbs of the body.

In theory, fatigue occurs earlier in LH pyramids, as the practitioner is already exhausted when reaching series with heavy weight. It has been reported^[26] that the use of maximal loads and low repetitions exerts pressure on the muscular nervous system by calling on fast-moving motor units and changes the nervous activity of the muscle, thereby increasing muscle strength. This suggests that LH may produce lower strength outcomes than HL. However, in practice, HL also requires an extensive warm-up before reaching the highest workloads.

Miller^[24] compared the HL and HL methods and concluded that the most important training bout should be performed first to reduce the effects of fatigue and allow for a greater number of repetitions to be performed. However, the protocol only included bench press as an exercise, though, as previously discussed in the present work, the effects may differ between the upper and lower limbs. The protocol also comprised only three sessions and five volunteers and only compared the number of repetitions between the two methods.

In sum, comparisons between HL and LH concerning strength gains are equivocal. This could mean that they produce different gains based on the type of contraction, as only isometric strength was evaluated in Leighton et al.^[20] Also, the effect size is high in Miller,^[24] as only a few participants were included in the study.

Comparison between Half-Triangle and Triangle Pyramids

Increasing, decreasing, and triangle pyramids affect strength, hypertrophy, and power similarly, but only triangle pyramids are likely to improve endurance. However, workload is lower in half-triangle versus triangle pyramids (Table 1).

Comparison of Triangle Methods

As pointed out by Mohammadi et al.,^[26] research outputs on triangle pyramids are conflicting. Previous studies have suggested that two different triangle pyramidal exercises lead to similar strength, endurance, hypertrophy, and anaerobic power outcomes, and also that different pyramidal patterns produce different outcomes based on which body limb is trained. Triangle pyramids can be compared as follows:

• Mohammadi et al.^[26] showed that ASYM versus SYM pyramids produced higher absolute power gains when the movement was executed at the same speed in the two methods. Other variables, such as strength, endurance, body weight, and hypertrophy of the upper and lower limbs, were similar.
• As the diet was not controlled in this study, the lack of a significant difference between the body weight in ASYM versus SYM pyramidal training was discussed, and it was suggested that SYM pyramids may produce leaner athletes.
• ASYM and SYM pyramids (Table 1) offer a similar training volume at high intensity and endurance, except that the overall training volume is lower in ASYM versus SYM pyramidal training.
• In theory, RP training offers the same advantage as ASYM pyramids but with a slightly higher endurance training volume (Table 1). In practice, the first sets appear to be warm-up sets, as they are not conducted to fatigue. The limited research on this method suggests that it should be avoided ^[13].

Discussion and Conclusion

Pyramidal and general resistance training induce cardiovascular, endocrinal, and neural adaptations, as well as changes in muscle composition and size. This results in an increase in strength, power, hypertrophy, and local muscle endurance. Strength and hypertrophy outcomes are comparable between traditional and pyramidal training,^[2] except that triangle pyramids likely produce greater endurance as regards the dose-dependent relationship between outcomes and training volume. However, to our knowledge, this has not been investigated experimentally to date.

Endurance outcomes in resistance training are surprising in terms of the specificity principle, which holds that two different kinds of training produce distinct adaptations. In accordance with this principle, resistance training tends to improve anaerobic filial and increase myofiber size and their contractile properties, while endurance training results in an improvement of the aerobic filial with a decrease in myofiber size and contractile properties.^[37] Reiss et al.^[31] suggested that concurrent methods of training interfere with each other, overwhelming the body’s capacity to compensate for the stimulation. In practice, interferences occur in the repetition zone of five to ten RM, when the anaerobic threshold is greater than 75% to 85% of the Vo2 max. In other words, strength and cardiovascular training are compatible, but intense cardiovascular training should be avoided while training for muscular hypertrophy.

In contrast, the impact of strength training for endurance athletes is not clear. In Tanaka et al.,^[37] resistance training improved short- and long-term endurance in beginners and well-trained athletes. The authors suggested that both types of training, aside from their different adaptations mentioned above, resulted in the same changes from type IIX to type IIA myofibers. In addition, resistance training improved the lactate threshold in untrained individuals, thereby delaying the onset of fatigue in endurance training. However, the authors stated that resistance training should be specifically adapted to each endurance sport, reporting that a resistance training method used in cyclists was inefficient on swimmers. In addition, it is possible that strength training may limit the development of maximal aerobic capacity.^[16]

In short, the pyramidal method is an effective method for training for strength, hypertrophy, and power while having the added benefit of enhancing endurance. This suggests that the pyramidal method is a good candidate for athletes who practice wrestling, as combat training involves aerobic training interspersed with anaerobic effort.^[26] Although the use of resistance in addition to endurance training is an interesting topic, the practice of resistance training should be carefully considered in light of the type of endurance sport, the training experience of the athlete (an improvement in the lactic threshold was only observed for beginners), the intensity of the endurance session (lower than 75 to 85% of Vo2max), and its potential on the maximal aerobic capacity. Further research could investigate the benefits of pyramidal training compared with periodization, including separate endurance and strength training.

Research has shown that different triangle pyramidal methods, such as flat or narrow pyramids, result in similar adaptations as resistance training.^[26] However, the resulting power is significantly higher in ASYM pyramids compared with SYM pyramids, while it was shown (though the finding is controversial) that athletes following a SYM pyramid training were leaner.^[26]

Existing literature suggests also that RP should be avoided, but at the same time outlined that studies on this topic are rare.^[13] A reasonable hypothesis is that first series in RP protocol should be conducted to fatigue in order to maximize endurance gains.

From a practitioner’s point of view, half-triangle pyramids are more efficient than traditional and triangle pyramids, as they produce similar strength and hypertrophy outcomes with a lower training volume. However, they also likely result in less local muscle endurance in light of the dose-dependent relationship with training volume. HL and LH are two ubiquitous half-triangle methods in which the weight is increased or decreased between each set. The differences between the two methods are equivocal, which could be due to the different effect sizes in prior studies. To the best of our knowledge, the impact of contraction type in HL versus LH pyramids has not been investigated to date. Ambiguity in terms of strength gains between these two types of pyramidal training could also mean that, from the practitioner's perspective, differences between the two methods are undetectable.

The effect of pyramidal training on body limbs was investigated by Costa et al.,^[9] Leighton et al.^[20] and Mohammadi et al.^[26] In Costa et al.,^[9] the authors showed that pyramidal training decreased lower limb activity during a single bout of pyramidal training compared with traditional training. This is consistent with Leighton et al.,^[20] who showed that LH Delorme training and Oxford HL training significantly affected the upper limbs but not the legs and back. However, encouragingly, Mohammadi et al.^[26] suggested that the impact of different types of pyramidal training on the body and upper limbs did not differ significantly.

Elsewhere, studies have demonstrated that pyramidal training is an alternative to traditional training for disabled or aging individuals,^[1][32] though muscle electrical activity differs significantly between the pyramidal methods depending on the repetition zones.^[33]

The suitability of pyramidal training for disabled or aging individuals, as well as for well-trained athletes^[2] suggests that pyramidal training is an effective method of resistance training for program variation across these populations.