Comparative effects of single vs. multiple-set resistance training on neuromuscular performance and muscle morphology in sedentary men

Abstract

Background

This study investigated the differential effects of single-set (SS) and multiple-set (MS) resistance training on muscle strength, hypertrophy, and neuromuscular performance in sedentary young men. Understanding how training volume influences early adaptations is essential for optimizing resistance training prescriptions in untrained populations.

Methods

Thirty-four sedentary males were randomly assigned to SS (n = 12), MS (n = 11), or control (CG, n = 11). The training groups completed an eight-week resistance training program performed twice per week, consisting of seven exercises with a maximum of ten repetitions each. The SS group performed one set per exercise, whereas the MS group performed three sets. Pre- and post-intervention assessments included anthropometry (body fat, lean mass, limb circumferences) and neuromuscular tests: handgrip strength, vertical jump, 20-m sprint, Yo-Yo IR-1, medicine-ball throws, and one-repetition maximum (1-RM) bench press and squat.

Results

The MS protocol induced greater hypertrophic adaptations (right and left leg muscle cross-sectional area: +11.3%) compared with SS (~ 6–8%) and CG. Strength gains were also superior in MS for bench press (+ 19.8%) and squat (+ 14.8%). Improvements in vertical jump (+ 6.4%) and Yo-Yo IR1 performance (+ 3.2%) were more pronounced in MS, while SS produced moderate but significant gains across most performance outcomes.

Conclusions

Both SS and MS resistance training improved strength, power, and morphological characteristics after eight weeks; however, the multiple-set protocol produced more robust hypertrophic and neuromuscular adaptations. These findings reinforce the presence of a volume-dependent dose–response relationship in the initial phases of resistance training for untrained individuals.

Trial registration

ClinicalTrials.gov NCT07337304. Registered on 14 December 2025. Retrospectively registered.

Supplementary Information

The online version contains supplementary material available at https://doi.org/10.1186/s13102-026-01874-8.

Introduction

Resistance training (RT) is widely recognized as the primary strategy to enhance muscle strength and mass. Adaptations elicited by RT depend primarily on acute program variables such as training frequency, intensity, volume, and inter-set rest intervals [1–4]. In this context, these variables are considered among the most critical factors for optimizing muscular strength and hypertrophy [2–5]. Previous evidence has described a nonlinear (inverted-U) association between weekly training volume and hypertrophic responses, underscoring the need for balanced loading within resistance programs [3, 4, 6]. Although training intensity, frequency, rest intervals, repetition tempo, and exercise order can also influence the magnitude of adaptation [5, 7–11], training volume is widely regarded as an important determinant of hypertrophic responses [3, 4, 12]. Accurate quantification of training volume commonly defined as sets × repetitions × load—is therefore essential for equating total work across interventions [10, 12–14].

A dose–response relationship between RT volume and increases in muscle strength and mass is generally accepted [4, 11, 15, 16]. Recent systematic reviews and meta-analyses have further clarified the dose–response relationship between resistance training volume and muscular adaptations [10, 12]. However, direct comparisons of single-set and multiple-set protocols have produced conflicting findings, likely due to differences in participants’ training status, program duration, and relative intensity [7, 10, 11, 17, 18]. Meta-analytic data in untrained or recreationally active individuals tend to support a positive association between weekly set number and hypertrophy [4, 19], whereas other reviews have reported that higher set volumes do not always yield superior adaptations when total workload is matched across training protocols [15, 20]. More recent studies, conversely, indicate greater improvements in both strength and hypertrophy following multi-set protocols [11, 20].

Given these discrepancies and the increasing number of recent investigations examining resistance training volume, further research is warranted to clarify the specific role of set volume in modulating muscular adaptations. Accordingly, the present study examined how differences in set volume influence muscle strength, power, and morphology by comparing the effects of single-set and multi-set resistance training programs in sedentary male participants. Considering that resistance training volume may also influence broader performance outcomes, including neuromuscular performance (e.g., power and speed), these variables were included as additional outcome measures in the present study [3, 4, 7]. These adaptations are likely mediated by cumulative mechanical and metabolic stress, which may affect neuromuscular systems [3, 20].

Methods

Study design and participants

The study was conducted over a 12-week period. Weeks 1–2 were allocated to participant familiarization, baseline testing, and instruction in correct resistance exercise technique. The main training phase lasted eight weeks (Weeks 3–10), during which the assigned exercise protocols were implemented. Week 11 was reserved for post-testing, and Week 12 for data verification and processing. The sample size was estimated using the G*Power 3.1 software program. Data obtained from previous studies were used for this estimation [21]. The calculation was based on an effect size of 0.25, an alpha level (α) of 0.05, and a statistical power (1–β) of 0.80. As a result, a minimum of 34 participants was required for inclusion in the study. Participants were randomly assigned to one of three groups: single-set (SS), multiple-set (MS), or control (CG). Allocation was performed using a computer-generated randomization sequence prepared by an independent researcher not involved in data collection or training supervision. Allocation concealment was ensured using sealed opaque envelopes opened only after baseline assessments were completed. Due to the nature of the intervention, participants and trainers were not blinded; however, outcome assessors were not involved in the training sessions. Both SS and MS groups completed structured resistance training programs for eight weeks, while the CG maintained their normal daily routines without participating in any structured physical activity. Pre- and post-intervention assessments included measurements of muscle strength, power, speed, endurance, and body composition.

Body Fat Percentage (BFP), Fat-Free Mass (FFM) and Body Mass Index (BMI).

Body composition variables including body fat percentage (BFP), Fat-Free Mass (FMM), and body mass index (BMI) were determined using a bioelectrical impedance analyzer (BIA; Tanita SC-330, Tanita Corp., Tokyo, Japan). Participants abstained from strenuous activity for 12 h and from food or fluid intake for 4 h before testing, and were instructed to avoid caffeine and alcohol for 24 h. Measurements were conducted between 08:00 and 10:00 a.m. under fasting conditions. All assessments were performed by the same investigator following standardized procedures. Participants wore light clothing, removed all metal accessories, and were barefoot during testing. Standing on the device’s electrodes with arms relaxed at their sides, participants maintained a stable posture while data were recorded. This protocol minimized procedural variability and ensured reproducible measures of BFP, FFM, and BMI [22].

Circumference measurements

Circumference measurements were taken in centimeters using a Gulick anthropometric tape (± 1 mm precision) in accordance with the International Society for the Advancement of Kinanthropometry (ISAK) standards. Participants stood in the anatomical position. Shoulder circumference was measured just below the acromion at the most prominent portion of the deltoid; chest at the level of the fourth costal cartilage anteriorly and the inferior angle of the scapula posteriorly; biceps at the thickest part of the relaxed arm; waist at the umbilical level; hips at the symphysis pubis anteriorly and the maximal gluteal protuberance posteriorly; thighs at the thickest region of the quadriceps; and calves at the maximum girth of the gastrocnemius muscle. Each site was measured twice, and the mean value was used for analysis. When discrepancies greater than 0.5 cm were detected, a third measurement was taken and the mean of the two closest readings was recorded [22].

20-Meter Sprint Test.

Sprint performance was evaluated over a 20 m distance. Prior to testing, participants completed a standardized 5-minute dynamic warm-up consisting of lunge walks (15 m), bodyweight squats (12 repetitions), calf raises (15 repetitions), and two progressive 20 m sprints. Each participant performed three maximal sprint trials with 3–5 min of passive rest. Sprint times were recorded using a dual-beam photocell timing system (SmartSpeed PT; Fusion Sport, Australia), and the fastest trial was used for analysis.

Vertical jump test

Following a 5-minute warm-up of light jogging and dynamic lower-limb activation (jump squats, single-leg squats, calf raises), participants performed countermovement jumps on a Smart Jump platform (Fusion Sport, Australia). The system automatically measured flight time with 0.001 s accuracy and calculated jump height in centimeters. Participants kept their hands on the hips throughout to minimize arm swing effects. Three trials were performed with 2–3 min of passive rest, and the highest value was retained for analysis [23].

Yo-Yo intermittent recovery test level 1 (Yo-Yo IR1)

Participants completed 2 × 20 m shuttle runs at progressively increasing speeds guided by pre-recorded audio signals. Each shuttle was followed by a 10-second active recovery within a 5 m zone. The test concluded when participants failed to maintain the required pace on two consecutive occasions. The total distance covered, including the final incomplete shuttle, was recorded. VO₂max (mL·kg⁻¹·min⁻¹) was estimated as (Distance × 0.0084) + 36.4. The Yo-Yo IR1 test was included to assess intermittent endurance performance.

Handgrip strength test

Maximal isometric handgrip strength was measured using a digital dynamometer (Takei Grip-D, Tokyo, Japan). Participants stood upright a with the dynamometer beside the body and the elbow fully extended. Three trials were performed for each hand with 2–3 min of rest. The highest value from either hand was used for analysis [24].

Estimation of one-repetition maximum (1-RM)

Following a warm-up of 5–10 repetitions at 40–60% of estimated 1-RM, participants performed both bench press and squat exercises. Due to the participants being untrained, direct 1-RM testing was avoided to reduce injury risk. Load was increased incrementally by 5 kg, with 3–5 min of rest between attempts. The test was terminated when six repetitions could not be completed. The 1-RM was estimated using the Brzycki formula: 1-RM = Load / [102.78–2.78 × (Number of repetitions)]. All lifts were performed under the supervision of certified strength coaches to ensure consistency and safety [25].

Overhead and backward medicine ball throw

After a 5-minute upper-body warm-up (shoulder press, lateral raise, scapular mobility drills, and Cat–Cow movements), participants performed three overhead and three backward throws using a 3-kg medicine ball. One to two minutes of rest was provided between trials. The distance from the start line to the first ground contact point of the ball was measured, and the best throw was recorded. The medicine ball throw test was included to assess upper-body explosive performance.

Rating of Perceived Exertion (RPE)

Perceived exertion during resistance training was evaluated using the OMNI-Resistance Exercise Scale (OMNI-RES 0 = “extremely easy,” 10 = “extremely hard”). The scale was explained before each session and participants reported their exertion immediately post-exercise under investigator supervision. Mean session RPE values were used to monitor training intensity across the intervention [26].

Resistance training design

The resistance training (RT) program was conducted twice weekly on non-consecutive days to ensure a 48-hour recovery interval between sessions. All training sessions were held between 14:30 and 16:00 h under controlled laboratory conditions. Each session began with a 10-minute standardized warm-up consisting of light aerobic exercise and submaximal resistance movements performed at 30–40% of 1-RM. Training intensity was set at 60–70% of individual 1-RM for 10–12 repetitions. To maintain the intended relative intensity throughout the intervention, training loads were increased whenever participants were able to comfortably complete 12 repetitions with proper technique. No additional 1-RM testing was performed during the intervention period. Two training sessions were structured as follows: Session A: Machine Leg Press, Lat Pulldown, Dumbbell Chest Press, Dumbbell Lateral Raise, Standing Dumbbell Biceps Curl, Cable Triceps Pushdown, and Back Extension. Session B: Machine Leg Curl, Seated Cable Row, Dumbbell Chest Fly, Dumbbell Shoulder Press, Dumbbell Hammer Curl, Dumbbell Triceps Kickback, and Hanging Leg Raise. The single-set group (SS) performed one set of each exercise with 2–3 min of rest between exercises. The multiple-set group (MS) performed three sets of each exercise, with 60–90 s of rest between sets and 2–3 min between exercises. Exercise order and technique were identical between groups. All training sessions were supervised by certified strength and conditioning professionals to ensure proper form and participant safety. Upon completion of each session, participants engaged in a 5-minute active recovery phase involving light aerobic activity and static stretching of the major muscle groups to facilitate recovery and minimize fatigue.

A detailed overview of the resistance training protocols, including exercise selection, training intensity, and recovery structure, is presented in Table 1.

Table 1.

Overview of the single- and multiple-set resistance training protocols, including session scheduling, exercise selection, and recovery structure

CATEGORY	SS	MS
Training Days & Times	Monday & Thursday, 14:30–16:00	Tuesday & Friday, 14:30–16:00
Week	8 Weeks	8 Weeks
Training Intensity & Repetitions	1-RM %60–70, 10–12 reps.	1-RM %60–70, 10–12 reps
Rest Periods	2–3 min between exercises	60–90 s between sets, 2–3 min between exercises
Day 1 Exercises	Machine Leg Press, Lat Pull Down, Dumbbell Chest Press, Dumbbell Lateral Raise, Standing Dumbbell Biceps Curl, Cable Triceps Pushdown, Back Extension	The same
Day 2 Exercises	Machine Leg Curl, Seated Cable Row, Dumbbell Chest Fly, Dumbbell Shoulder Press, Dumbbell Hammer Curl, Dumbbell Triceps Kickback, Hang Leg Raise	The same
Recovery	Active recovery after training	Active recovery after training

1-RM = One-repetition maximum; SS = Single-set; MS = Multiple-set

Statistical analysis

Since several variables did not meet the assumptions of normality, a non-parametric approach was applied. Pre–post differences within each participant were expressed as delta (∆) values, and these scores were compared among the three groups (Control, Single-Set, and Multi-Set) using the Kruskal–Wallis test, reported as Chi-square (H) statistics in SPSS output. When significant main effects were found, pairwise comparisons were performed using the Mann–Whitney U test with Bonferroni-adjusted significance levels. Results are presented as mean ± standard deviation (SD), and statistical significance was accepted at p < 0.05.

Results

The mean age, height, body weight (BW), body mass index (BMI), body fat percentage (BFP), and Fat-free mass (FFM) of the volunteers participating in the study are shown in Table 2.

Table 2.

Baseline characteristics of participants by group (Mean (SD))

Variable	CG (n = 11)	SS (n = 12)	MS (n = 11)
Age (years)	20.64 (0.92)	20.67 (2.19)	20.55 (1.29)
Height (cm)	174.27 (8.57)	176.17 (10.20)	175.64 (7.43)
Body mass (kg)	63.95 (8.19)	69.11 (16.86)	67.74 (15.31)
BMI (kg/m²)	20.99 (1.59)	22.00 (3.39)	21.79 (3.42)
Body fat (%)	14.02 (6.47)	14.93 (5.38)	14.31 (6.46)
Fat-Free Mass (kg)	52.33 (8.42)	55.62 (12.68)	54.90 (10.98)

CG = Control Group; SS = Single-Set; MS = Multiple-Set

Table 3 presents pre- and post-intervention body composition and anthropometric measurements for each group, expressed as mean ± standard deviation (SD).

Table 3.

Pre- and post-intervention body composition and anthropometric measurements of participants (mean ± SD)

Parameter	CG- Pre	CG- Post	SS- Pre	SS- Post	MS- Pre	MS- Post
BMI (kg/m²)	21.75 ± 3.44	21.99 ± 3.55	21.30 ± 1.86	21.23 ± 1.83	21.79 ± 3.42	21.71 ± 3.39
BFP (%)	14.71 ± 5.58	15.05 ± 5.95	14.30 ± 6.24	14.14 ± 6.23	14.31 ± 6.46	13.84 ± 6.47
FFM (kg)	55.28 ± 13.24	54.94 ± 13.28	52.91 ± 8.27	53.18 ± 8.41	54.90 ± 10.98	56.11 ± 11.54
Shoulder Circumference (cm)	105.55 ± 10.70	105.82 ± 10.93	106.71 ± 9.08	107.25 ± 9.56	105.82 ± 10.34	107.10 ± 10.68
Chest Circumference (cm)	92.18 ± 11.66	92.64 ± 12.12	91.42 ± 7.49	91.75 ± 7.88	92.00 ± 7.97	92.72 ± 7.63
Right Arm Circumference (cm)	26.27 ± 3.88	26.36 ± 4.03	26.25 ± 3.14	26.67 ± 3.47	27.09 ± 3.81	28.81 ± 4.02
Left Arm Circumference (cm)	26.18 ± 3.74	26.27 ± 3.90	26.17 ± 3.24	26.58 ± 3.58	27.00 ± 3.66	28.34 ± 4.29
Waist Circumference (cm)	79.09 ± 11.65	80.00 ± 12.16	75.71 ± 7.21	75.29 ± 6.74	76.82 ± 10.90	75.27 ± 10.92
Hip Circumference (cm)	94.73 ± 13.20	95.06 ± 13.42	95.42 ± 3.65	95.33 ± 3.60	96.91 ± 8.20	96.76 ± 8.16
Right Thigh Circumference (cm)	50.82 ± 6.82	51.00 ± 7.07	50.25 ± 3.19	50.33 ± 3.26	52.27 ± 4.34	52.95 ± 4.51
Left Thigh Circumference (cm)	50.91 ± 6.79	51.09 ± 7.05	50.25 ± 3.39	50.33 ± 3.45	52.36 ± 4.13	52.98 ± 4.26

(BMI = Body Mass Index; BFP = Body Fat Percentage; FFM = Fat-Free Mass; CG = Control Group; SS = Single-Set; MS = Multiple-Set.)

Pre- and post-intervention motor performance parameters are presented in Table 4 as mean ± standard deviation (SD).

Table 4.

Pre- and post-intervention motor performance parameters of the participants (mean ± SD)

Parameter	CG- Pre Test	CG- Post Test	SS- Pre Test	SS-Post Test	MS- Pre Test	MS- Post Test
Right-Handed Grip (kg)	42.35 ± 10.48	41.17 ± 11.70	45.21 ± 7.61	48.93 ± 8.02	47.49 ± 10.52	52.87 ± 11.03
Left-Handed Grip (kg)	40.26 ± 9.98	39.47 ± 11.15	43.80 ± 7.62	46.65 ± 7.72	45.45 ± 10.08	50.62 ± 10.68
Vertical Jump (cm)	40.45 ± 5.12	39.93 ± 5.61	47.35 ± 8.15	48.40 ± 8.09	39.96 ± 7.57	42.51 ± 8.09
Medicine Ball Overhead (m)	6.69 ± 1.71	6.30 ± 1.97	7.02 ± 1.85	7.57 ± 1.94	6.86 ± 1.47	8.54 ± 1.45
Medicine Ball Back (m)	8.23 ± 1.97	7.98 ± 2.27	8.73 ± 1.94	9.47 ± 2.00	8.46 ± 1.42	10.34 ± 1.77
20 m (sec)	3.27 ± 0.50	3.48 ± 0.66	2.95 ± 0.49	2.89 ± 0.50	3.07 ± 0.31	2.91 ± 0.32
Yo-Yo IR-1 (m)	39.31 ± 1.26	39.34 ± 1.75	40.88 ± 1.43	41.46 ± 1.66	40.74 ± 3.24	42.05 ± 3.18
1-RM Bench Press (kg)	42.27 ± 12.32	40.91 ± 15.30	44.17 ± 12.76	47.92 ± 11.77	41.36 ± 15.67	49.55 ± 17.81
1-RM Squat (kg)	56.82 ± 22.05	55.45 ± 22.19	57.50 ± 13.57	59.58 ± 13.39	61.36 ± 12.86	70.45 ± 14.57

(CG = Control Group; SS = Single-Set; MS = Multiple-Set.)

Between-group differences in body composition and anthropometric variables (∆ values) are summarized in Table 5.

Table 5.

Analysis of the Differences in Pre- and Post-Test Values of Selected body composition + anthropometric measurements of the Participants

Parameter	Groups	X	SD	X2	p	Difference
BF% (∆)	Control (n = 11)	0.34	0.54	17.922	0.001*	SS > CG MS > CG MS > SS
	SS (n = 12)	0.15	0.26
	MS (n = 11)	0.47	0.17
FFM(∆)	Control (n = 11)	− 0.34	0.77	19.867	0.001*	SS > CG MS > CG MS > SS
	SS (n = 12)	0.27	0.36
	MS (n = 11)	1.20	0.60
BMI (∆)	Control (n = 11)	0.23	0.41	6.014	0.049*	SS > CG MS > CG MS > SS
	SS (n = 12)	− 0.07	0.06
	MS (n = 11)	− 0.08	0.117
Shoulder Circumference (∆)	Control (n = 11)	0.27	0.46	10.398	0.006*	SS > CG MS > CG MS > SS
	SS (n = 12)	0.54	0.72
	MS (n = 11)	1.28	0.73
Chest Circumference (∆)	Control (n = 11)	0.45	0.52	3.090	0.213	CG = SS=MS
	SS (n = 12)	0.33	0.49
	MS (n = 11)	0.71	1.16
Right Arm Circumference (∆)	Control (n = 11)	0.09	0.53	17.959	0.001*	SS > CG MS > CG MS > SS
	SS (n = 12)	0.41	0.51
	MS (n = 11)	1.71	0.78
Left Arm Circumference (∆)	Control (n = 11)	0.09	0.53	9.686	0.008*	SS > CG MS > CG MS > SS
	SS (n = 12)	0.41	0.51
	MS (n = 11)	1.33	1.06
Waist Circumference (∆)	Control (n = 11)	0.90	1.4	13.793	0.001*	SS > CG MS > CG MS > SS
	SS (n = 12)	− 0.41	0.76
	MS (n = 11)	-1.54	1.2
Hip Circumference (∆)	Control (n = 11)	0.33	0.87	1.812	0.404	CG = SS=MS
	SS (n = 12)	− 0.08	0.28
	MS (n = 11)	− 0.14	1.03
Right Thigh Circumference (∆)	Control (n = 11)	0.18	0.60	4.434	0.109	CG = SS=MS
	SS (n = 12)	0.08	0.28
	MS (n = 11)	0.67	0.87
Left Thigh Circumference (∆)	Control (n = 11)	0.18	0.60	4.433	0.109	CG = SS=MS
	SS (n = 12)	0.08	0.28
	MS (n = 11)	0.61	0.74

(*p < 0.05; ∆: Difference; BF%: Body Fat Percentage; FFM: Fat-Free Mass; BMI: Body Mass Index; X: Mean; SD: Standard Deviation, CG = Control Group; SS = Single-Set; MS = Multiple-Set.)

Significant between-group differences were observed in several body composition and anthropometric parameters following the eight-week intervention. In terms of body fat percentage (BF%), both the single-set (Set-1) and multi-set (Set-3) groups showed significant reductions compared with the control group (H = 17.922, p = 0.001), with the multi-set group exhibiting the greatest decrease. Similarly, fat-free mass (FFM) increased significantly across the training groups (H = 19.867, p = 0.001), and post-hoc analyses confirmed that Set-3 achieved higher gains than both Set-1 and control participants (Z = − 2.349, p = 0.019). A significant group effect was also detected for body mass index (BMI; H = 6.014, p = 0.049). Post-hoc comparisons revealed greater BMI reductions in both the SS and MS groups compared with the control group (p < 0.05). In addition, the reduction in BMI was significantly greater in the MS group than in the SS group (p < 0.05).For shoulder circumference, the overall difference among groups was significant (H = 10.398, p = 0.006). Post-hoc comparisons revealed greater increases in both the SS and MS groups compared with the control group. Furthermore, the increase in shoulder circumference was significantly greater in the MS group than in the SS group (p < 0.05). Significant improvements were also observed for right and left arm circumferences (H = 17.959 and 9.686, respectively; p < 0.01). Post-hoc comparisons revealed greater increases in both the SS and MS groups compared with the control group. Furthermore, the increases in right and left arm circumferences were significantly greater in the MS group than in the SS group (p < 0.05). In addition, waist circumference decreased significantly in favor of Set-1 and Set-3 compared to control (H = 13.793, p = 0.001), again with the multi-set group showing the largest magnitude of change. Conversely, no significant differences were detected among groups for chest, hip, or thigh circumferences (p > 0.05).

Between-group differences in motor performance parameters are presented in Table 6.

Table 6.

Difference analysis of pre- and post-test in some motor performance parameters

Parameter	Grups	X	SD	X2	p	Difference
Right Hand Grip (∆)	Control (n = 11)	0.90	2.7	18.865	0.001*	SS > CG MS > CG MS > SS
	SS (n = 12)	5.12	2.8
	MS (n = 11)	7.42	1.7
Left Hand Grip (∆)	Control (n = 11)	0.79	1.5	28.446	0.001*	SS > CG MS > CG MS > SS
	SS (n = 12)	2.85	0.85
	MS (n = 11)	5.17	1.04
Vertical Jump (∆)	Control (n = 11)	0.51	1.2	25.220	0.001*	SS > CG MS > CG MS > SS
	SS (n = 12)	1.05	0.33
	MS (n = 11)	2.54	0.94
Medicine Ball Overhead (∆)	Control (n = 11)	0.39	0.59	27.474	0.001*	SS > CG MS > CG MS > SS
	SS (n = 12)	0.54	0.21
	MS (n = 11)	1.67	0.38
Medicine Ball Backward (∆)	Control (n = 11)	0.24	0.61	25.593	0.001*	SS > CG MS > CG MS > SS
	SS (n = 12)	0.73	0.30
	MS (n = 11)	1.87	0.61
20 m (∆)	Control (n = 11)	0.21	0.22	23.718	0.001*	SS > CG MS > CG MS > SS
	SS (n = 12)	− 0.065	0.054
	MS (n = 11)	− 0.16	0.087
Yo Yo IR-1 (∆)	Control (n = 11)	0.030	0.85	13.553	0.001*	SS > CG MS > CG MS > SS
	SS (n = 12)	0.58	0.56
	MS (n = 11)	1.30	0.56
1-RM Bench Press (∆)	Control (n = 11)	1.36	5.5	18.965	0.001*	SS > CG MS > CG MS > SS
	SS (n = 12)	3.75	2.2
	MS (n = 11)	8.18	2.5
1-RM Squat (∆)	Control (n = 11)	1.36	3.2	22.278	0.001*	SS > CG MS > CG MS > SS
	SS (n = 12)	0.08	0.28
	MS (n = 11)	0.61	0.74

(X: Mean; SD: Standard Deviation CG: Control Group, SS: Single Set, MS: Multiple Set)

Significant between-group differences were observed in several motor performance parameters following the eight-week resistance training intervention. Both right- and left-hand grip strengths increased significantly (H = 18.865 and 28.446, respectively; p < 0.001), and post-hoc analyses confirmed progressive improvements across groups (MS > SS> CG). Similarly, vertical jump height improved significantly in both training groups (H = 25.220, p < 0.001), with the multi-set protocol producing the greatest enhancement (Z = − 2.932, p = 0.003). Medicine ball throw performance exhibited parallel trends. Significant improvements were observed in both overhead and backward throws (H = 27.474 and 25.593, respectively; p < 0.001). Post-hoc comparisons revealed greater improvements in both the SS and MS groups compared with the control group. Furthermore, the improvements observed in the MS group were significantly greater than those observed in the SS group (p < 0.05). Sprint performance over 20 m also improved significantly in both training groups (H = 23.718, p < 0.001), again showing the most pronounced gains in the multi-set condition (Z = − 3.651, p = 0.001). The Yo-Yo Intermittent Recovery Test Level 1 (Yo-Yo IR1) results indicated a significant group effect (H = 13.553, p = 0.001). Both training groups improved relative to control. Although the multi-set group showed higher mean improvements than the single-set group, the difference did not reach statistical significance (p = 0.067). Strength-specific measures also revealed significant adaptations. The 1-RM Bench Press (H = 18.915, p < 0.001) and 1-RM Squat (H = 22.278, p = 0.001) both improved significantly, with MS producing greater post-test gains compared with SS (Z = − 2.265, p = 0.024).

Discussion

This study investigated the effects of different set volumes on anthropometric and motor performance outcomes in sedentary men, aiming to clarify the dose–response relationship between training volume and neuromuscular adaptations. The findings revealed that multi-set (MS) resistance training induced significantly greater improvements in muscle strength, power, and body composition compared to the single-set (SS) protocol. These outcomes are consistent with previous evidence supporting the superiority of multi-set programs for enhancing strength and hypertrophy [3, 4, 7, 12, 27–30]. Although several studies report similar findings, others have shown comparable adaptations following single- and multi-set training [15, 20, 31]. Such discrepancies likely stem from variations in training duration, session frequency, total volume, and population characteristics [3, 11]. Among these, training duration appears particularly influential. Short-term interventions (6–8 weeks) often demonstrate significant benefits from higher set volumes, whereas longer-term programs may attenuate between-group differences as adaptation plateaus.

In the present study, greater gains were observed in the MS group compared with both the control and SS groups across nearly all motor performance indicators, including vertical jump, sprint performance, handgrip strength, 1-RM upper and lower body strength, and medicine ball throw performance. These findings are in line with previous research indicating that higher training volumes generally produce superior neuromuscular adaptations, particularly in untrained individuals [7, 10, 12, 32]. Conversely, some studies have reported no additional benefits of higher set numbers, particularly in untrained or elderly populations [20, 33–36]. These findings suggest that baseline training status may influence responsiveness to training volume. In novice individuals, even a single set may provide a sufficient stimulus to induce meaningful adaptations, whereas higher volumes may be required to elicit further improvements as training progresses [7, 10, 37, 38]. From a broader methodological perspective, the adaptive stimulus of resistance training is influenced not only by the number of sets performed, but also by total work, repetition tempo, time under tension, proximity to failure, rest interval duration, and fatigue accumulation [3, 4, 20, 39]. Accordingly, a single set performed under more demanding conditions may impose a greater stimulus than a superficially comparable set performed with lower effort [40]. Therefore, the present findings likely reflect the combined influence of training volume and overall training dose rather than an isolated effect of set number alone [3, 4, 20, 41].

Mechanistically, the superiority of multi-set training can be explained by its cumulative effect on key stimuli associated with muscular adaptation. As training volume increases, total workload also increases, resulting in greater cumulative mechanical tension and metabolic stress [3, 4]. These factors are considered important drivers of hypertrophy and strength development [3, 4, 42]. In addition, higher training volumes may contribute to greater recruitment of higher-threshold motor units, which may support improvements in both maximal strength and explosive performance [5, 43]. In the present study, multi-set training also enhanced Yo-Yo IR1 performance, reflecting improvements in intermittent endurance capacity. These findings may be related to the greater overall workload associated with multi-set training, which could contribute to improved tolerance to repeated high-intensity efforts [43]. Thus, beyond localized muscular adaptations, set volume may influence broader performance outcomes [3, 4]. Several methodological considerations must be acknowledged. Individual variability in recovery capacity, nutritional habits, and sleep patterns may have contributed to differences in adaptive magnitude. The relatively short intervention period (eight weeks) limits interpretation of long-term adaptation patterns. Additionally, while the study controlled for intensity and exercise selection, subtle differences in effort, rest intervals, or inter-session recovery may have influenced the magnitude of improvement. Future research should extend training duration and explore different set configurations to further clarify volume-dependent adaptations [5, 20].

Taken together, the present findings support the notion that increasing set volume enhances not only strength and hypertrophy but also explosive performance and intermittent endurance capacity. This study was reported in accordance with the CONSORT guidelines, and no adverse events were observed during the intervention period.

Conclusion

The number of sets performed during resistance training represents a critical determinant of adaptive response. After eight weeks of structured training, the multi-set protocol demonstrated superior improvements in muscle strength, hypertrophy, power, and aerobic capacity compared to single-set training. These findings confirm a dose–response relationship between training volume and adaptation magnitude. Practically, while single-set training may remain sufficient for time-efficient health-oriented exercise, multi-set programs appear more effective for maximizing performance-related and structural adaptations. Future research should integrate molecular, neural, and metabolic analyses to elucidate the mechanisms through which training volume modulates adaptation, ultimately guiding individualized and evidence-based resistance training prescriptions.

Authors’ contributions

I.A.C analysed and interpreted the data and were involved in writing the first draft of the manuscript. I.A.C. made substantial contributions to the conception and design of the work, as well as writing and editing the manuscript’s final version. M.E.K. contributed to data interpretation, writing, and editing of the manuscript’s final version. All authors read and approved the final manuscript.

Funding

No specific funding was received for this study.

Data availability

The data that support the findings of this study are available from the corresponding author upon reasonable request. The data are not publicly available due to privacy and ethical restrictions.

Declarations

Ethics approval and consent to participate

This study was conducted in accordance with the principles of the Declaration of Helsinki and was approved by the Ethics Committee of Inönü University (Approval No: 2022/2525). Informed consent was obtained from all participants. The study protocol was retrospectively registered at ClinicalTrials.gov (Identifier: NCT07337304).

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.