Effects of Resistance Training Performed with Different Loads in Untrained and Trained Male Adult Individuals on Maximal Strength and Muscle Hypertrophy: A Systematic Review

Abstract

The load in resistance training is considered to be a critical variable for neuromuscular adaptations. Therefore, it is important to assess the effects of applying different loads on the development of maximal strength and muscular hypertrophy. The aim of this study was to systematically review the literature and compare the effects of resistance training that was performed with low loads versus moderate and high loads in untrained and trained healthy adult males on the development of maximal strength and muscle hypertrophy during randomized experimental designs. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines (2021) were followed with the eligibility criteria defined according to participants, interventions, comparators, outcomes, and study design (PICOS): (P) healthy males between 18 and 40 years old, (I) interventions performed with low loads, (C) interventions performed with moderate or high loads, (O) development of maximal strength and muscle hypertrophy, and (S) randomized experimental studies with between- or within-subject parallel designs. The literature search strategy was performed in three electronic databases (Embase, PubMed, and Web of Science) on 22 August 2021. Results: Twenty-three studies with a total of 563 participants (80.6% untrained and 19.4% trained) were selected. The studies included both relative and absolute loads. All studies were classified as being moderate-to-high methodological quality, although only two studies had a score higher than six points. The main findings indicated that the load magnitude that was used during resistance training influenced the dynamic strength and isometric strength gains. In general, comparisons between the groups (i.e., low, moderate, and high loads) showed higher gains in 1RM and maximal voluntary isometric contraction when moderate and high loads were used. In contrast, regarding muscle hypertrophy, most studies showed that when resistance training was performed to muscle failure, the load used had less influence on muscle hypertrophy. The current literature shows that gains in maximal strength are more pronounced with high and moderate loads compared to low loads in healthy adult male populations. However, for muscle hypertrophy, studies indicate that a wide spectrum of loads (i.e., 30 to 90% 1RM) may be used for healthy adult male populations.

Dispersion of Knee Helical Axes during Walking after Maximal versus Resistant Strength Training in Healthy Subjects

“…In agreement with previous studies, both MT and RT groups had similar improvements in muscle strength, as demonstrated by MVC values at the training end [15]. However, no changes over time were detected in terms of knee HAs dispersion.…”

“…Strength training has been reported to influence joint stability by means of mechanical changes and modifications in neuromuscular control [11,12]. In this context, different intensity protocols, including maximal resistant (80-90% of one repetition maximum) and submaximal resistant (30-40% of one repetition maximum) voluntary contractions are adopted, inducing different mechanical loads and metabolic stresses aimed at generating neuromuscular and structural adaptations [13][14][15]. When considering strength gains, both types of training have been reported to induce benefits, but a superiority has been demonstrated in favor of maximal strength training [16,17].…”

“…When considering strength gains, both types of training have been reported to induce benefits, but a superiority has been demonstrated in favor of maximal strength training [16,17]. Interestingly, these strength modifications often occurred in the absence of differences in terms of muscle hypertrophy, especially in the short term, where neuromuscular adaptations play a predominant role in strength amelioration [15,17]. In addition, neuromuscular adaptations have been reported after a single session of maximal or resistant training [13].…”

Comparison of Kinematics and Electromyographic Activity in the Last Repetition during Different Repetition Maximums in the Bench Press Exercise

“…The authors found that the 3-RM group increased their 1-RM bench press to a greater extent than the 10-RM group. This is logical because the ability to produce force is a result of a combination of muscle mass [ 5 ], neural factors [ 6 ], and the specificity of the load itself during resistance exercises [ 7 ]. However, the body of knowledge about how the kinematics is affected by the load when the set is taken to concentric failure is, to our understanding, not well studied or understood for the bench press exercise.…”

Physical exercise improved muscle strength and pain on neck and shoulder in military pilots

“…We extracted the following data from each included study: type of aircraft, total number of participants, age, height, weight, type of study, training site, training protocol, equipment, followup period, and outcomes. The primary outcomes were neck maximal voluntary isometric contractions (MVICs) (Lacio et al, 2021), including flexion, extension, left (Ltflx) and right (Rtflx) lateral flexion and the prevalence of neck pain (Ben Ayed et al, 2019). When included in our analysis, the units of the MVIC are unified and are typically reported as N or Nm.…”