TABLE 2.

Study characteristics.

Study (year)	Sample	Final sample size (dropouts) age (years mean ± SD)	Resistance training tasks(s) Characteristics Target Duration	EMG method Muscle(s) assessed	Outcome measure(s)
Randomized control trials
Rich and Cafarelli, 2000	N = 20 males	Resistance n = 10 (0) Control n = 10 (0) Sample (22.9 ± 2.1 yr)	Isometric resistance training. Quadriceps of dominant leg. Five sets of 10 brief MVC (3–5 s) 24 sessions, 8 weeks	Intramuscular EMG Vastus lateralis	Motor unit discharge rate
Pucci et al., 2006	N = 20 males	Resistance n = 10 (0) Control n = 10 (0) Sample (25.0 ± 5.5 yr)	Maximal Voluntary Contractions. Quadriceps. Three sets of 10 MVCs (MVC was held for 3 s with 3 s intervals intervening) with 2 min rest between sets. 9 sessions, 3 weeks	Intramuscular EMG Right vastus lateralis	Motor unit discharge rate
Vila-Chã et al., 2010	N = 30 males	Resistance n = 9 (1) (25.4 ± 4.2 yr) Control n = 8 (2) 27.0 ± 5.0 yr Endurance n = 10 (0) (26.1 ± 2.8 yr)	Variety of exercises. Trunk, bilateral upper, and lower limbs. Three bilateral leg press, leg extension, and leg curl, and four additional lateral pull down, bench press, exercise for the trunk flexors and for trunk extensors. 18 sessions, 6 weeks	Intramuscular EMG Vastus lateralis and vastus medialis obliquus	Motor unit discharge rate
Stock and Thompson, 2014	N = 26 males	Resistance n = 15 (0) Control n = 9 (2) Aged 24 ± 3 years	Conventional barbell deadlifts. Knee extensors. Two warm-up sets of five repetitions. Three minutes of rest was allotted between each set. As a means of progressive overload, 0.45–2.2 kg was added to the barbell for each training session. 25 repetitions per sessions. 20 sessions, 10 weeks	Surface EMG array. Vastus lateralis	Mean firing rate vs. recruitment threshold relationship Firing Rate at recruitment vs. recruitment threshold relationship
Vila-Chã and Falla, 2016	N = 30 males	Resistance n = 9 (1) (25.4 ± 4.2 yr) Control n = 8 (2) (27.0 ± 5.0 yr) Endurance n = 10 (0) (26.1 ± 2.8 yr)	Variety of exercises. Trunk, bilateral upper, and lower limbs. Three bilateral leg press, leg extension, and leg curl, and four additional lateral pull down, bench press, exercise for the trunk flexors and for trunk extensors. 18 sessions, 6 weeks	Intramuscular EMG Vastus lateralis and vastus medialis obliquus	Motor unit discharge rate
Non-randomized control trials
Del Vecchio et al., 2019a	N = 28 males	Resistance n = 13 (1) 23.9 ± 2.9 yr. Control n = 12 (2) 25.1 ± 2.9 yr.	Ballistic and isometric contractions Tibialis anterior Warm-up of (2 × 50, 2 × 70 1 × 90% of perceived MVF) followed by 3 MVCs then 40 maximal ballistic contractions (4 × 10 reps; 60 s with 1 min of recovery between sets), 4 min of rest, then 30 sustained isometric ramp contractions (3 × 10 reps; 60 s with 2 min of recovery). 12 sessions, 4 weeks (30 mins per session)	High density surface EMG Tibialis anterior	Motor unit discharge rate
Sterczala et al., 2020	N = 30 males	Resistance n = 16 (4) (20.7 ± 1.9 yr) Control n = 8 (2) (19.4 ± 2.5 yr)	Variety of lower limb exercises based on linear periodization model. Knee extensors. Back squats, front squats, Romanian deadlifts, knee extensions, leg presses, glute bridges, step ups, hamstring curls, and reverse hyperextensions. 3 sets of 12 repetitions during weeks 1–3, 3 sets of 8 repetitions during weeks 4–6 and 4 sets of 5 repetitions during weeks 7–8. 24 sessions, 8 weeks	5-pin surface EMG array. Vastus lateralis	Motor unit recruitment threshold Mean firing rate vs. recruitment threshold relationship

EMG, electromyography; NR, Not reported.