Table 3.
Characteristics of longitudinal human studies on maximal strength
| Study | Subjects | Intervention period | Muscle and stretching volume | Methods | Results (maximal strength increase) mean % changea |
|---|---|---|---|---|---|
| Abdel-Aziem and Mohammad [125] | n = 75 | 6 weeks |
Plantar flexors 5 × 30 s twice/day 5 days/week |
Contraction type: dynamic (concentric and eccentric) Control condition: separate passive control group Additional information: 1 IG with trained participants, 1 IG with untrained participants |
Trained participants: concentric peak torque 30°/sec + 9.11%, concentric peak torque 120°/sec + 11.64%, eccentric peak torque 30°/sec + 11.92%, eccentric peak torque 120°/sec + 12.54% Untrained participants: concentric peak torque 30°/sec – 0.25%, concentric peak torque 120°/sec + 14.51, eccentric peak torque 30°/sec + 11.96%, eccentric peak torque 120°/sec + 9.38% |
| Akagi and Takahashi [116] | n = 19 | 5 weeks |
Plantar flexors 3 × 2 min/day on 6 days/week |
Contraction type: isometric Control condition: contralateral control leg |
No significant changes |
| Caldwell et al. [126] | n = 30 | 2 weeks |
Quadriceps and hamstrings 3 × 30 s, either once or twice per day for 14 days |
Contraction type: isometric Control condition: contralateral control leg Additional information: 2 IGs, 1 IG stretched once/day, 1 IG stretched twice/day |
IG with 2 sessions/day + 7.1% in quadricep MVC No significant increase for both groups in hamstring MVC and quadricep MVC for IG with 1 session/day |
| Chen et al. [127] | n = 30 | 8 weeks |
Hamstrings 30 × 30 s/day 3 days/week |
Contraction type: isokinetic concentric at 60°/sec Control condition: separate passive control group Additional information: MVC tested in quadriceps as well |
MVC in flexion (hamstrings) + 8.67% MVC in extension (quadriceps) + 3.04% |
| Guissard and Duchateau [128] | n = 12 | 6 weeks |
Plantar flexors 10 min/day 5 times/week |
Contraction type: ballistic and isometric Control condition: contralateral control leg |
No significant changes |
| Ikeda and Ryushi [129] | n = 25 | 6 weeks |
Knee extensors 6 × 30 s/day 3 days/week |
Contraction type: isometric Control condition: separate passive control group |
MVC + 10.16% |
| Kokkonen et al. [130] | n = 38 | 10 weeks |
Lower extremity muscles, i.e., quadriceps, hamstrings, gluteus, abductors, adductors, plantar flexors, dorsiflexors 15 exercises: each 3 × 15 s/day 3 days/week |
Contraction type: dynamic 1RM Control condition: separate passive control group |
Knee flexion 1RM + 15.3% Knee extension 1RM + 32.4% |
| Konrad and Tilp [131] | n = 41 | 6 weeks |
Plantar flexors 4 × 30 s/day 5 days/week |
Contraction type: isometric Control condition: separate passive control group and contralateral control leg |
No significant changes |
| LaRoche et al. [132] | n = 29 | 4 weeks |
Hip extensors 10 × 30 s/day 3 days/week |
Contraction type: isokinetic hip extension at 60°/sec Control condition: separate passive control group |
Peak torque + 5.3% |
| Longo et al. [122] | n = 30 | 12 weeks |
Plantar flexors 2 exercises: each 5 × 45 s/day 5 days/week |
Contraction type: isometric Control condition: separate passive control group |
No significant changes |
| Marshall et al. [133] | n = 22 | 4 weeks |
Hamstrings 4 exercises: each 3 × 30 s/day 5 days/week |
Contraction type: isokinetic at 30°/sec and 120°/sec Control condition: separate passive control group |
No significant changes |
| Mizuno [123] | n = 35 | 8 weeks |
Plantar flexors 4 × 30 s/day 3 days/week |
Contraction type: dynamic 1RM Control condition: separate passive control group Additional information: 2 IGs, 1 with SS only and 1 combining SS with ES |
SS + 20.8% SS&ES + 22.4% |
| Nakamura et al. [43] | n = 40 | 4 weeks |
Plantar flexors 3 × 60 s/day 3 days/week |
Contraction type: isometric Control condition: separate passive control group Additional information: high-intensity and low-intensity static stretching groups |
No significant changes |
| Nakao et al. [134] | n = 30 | 4 weeks |
Hamstrings 1 × 5 min/day 3 days/week |
Contraction type: isometric and isokinetic at 60°/sec and 180°/sec Control condition: separate passive control group |
Peak torque 60°/sec + 10.55% Peak torque 180°/sec + 13.61% No significant changes in isometric testing |
| Nelson et al. [130] | n = 25 | 10 weeks |
Plantar flexors 4 × 30 s/day 3 days/week |
Contraction type: dynamic 1RM Control condition: separate passive control group and contralateral control leg |
1RM in intervened leg + 29% 1RM in control leg + 11% |
| Sato et al. [42] | n = 24 | 6 weeks |
Plantar flexors Group 1: 120 s/day 3 days/week Group 2: 360 s/day 1 day/week |
Contraction type: isometric at 30° plantar flexion, neutral and 15° dorsiflexion Control condition: uncontrolled Additional information: 2 IGs, 1 with 120 s/day 3 days/week and 1 with 360 s/day 1 day/week |
No significant changes |
| Simpson et al. [44] | n = 21 | 6 weeks |
Plantar flexor 3 min/day 5 days/week |
Contraction type: isometric Control condition: separate passive control group |
No significant changes |
| Warneke et al. [117] | n = 52 | 6 weeks |
Plantar flexors 60 min/day 7 days/week |
Contraction type: dynamic 1RM and isometric Control condition: separate passive control group and contralateral control leg |
MVC + 16.2% 1RM + 25.3% |
| Warneke et al. [120] | n = 69 | 6 weeks |
Plantar flexors 60 min/day 7 days/week |
Contraction type: isometric with extended and bent knee joint Control condition: separate passive control group |
MVC with extended knee joint + 18% MVC with bent knee joint + 9.58% |
| Warneke et al. [121] | n = 45 | 6 weeks |
Plantar flexors 60 min/day 7 days/week |
Contraction type: isometric with extended sand bent knee joint Control condition: separate passive control group and contralateral control leg |
MVC with extended knee joint + 9.44% MVC with bent knee joint + 4.84% |
| Warneke et al. [40] | n = 70 | 6 weeks |
Plantar flexors 60 min/day or 120 min each 7 days/week |
Contraction type: isometric Control condition: separate passive control group and contralateral control leg Additional information: 2 IGs, 1 IG stretched 60 min/day, 1 IG stretched 120 min/day |
MVC in 60-min group + 15.3% MVC in 120-min group + 22.9% |
| Warneke et al. [118] | n = 35 | 6 weeks |
Plantar flexors 10 min/day 7 days/week |
Contraction type: isometric Control condition: separate passive control group |
MVC + 10.5% |
| Wohlann et al. [124] | n = 44 | 6 weeks |
Lower extremity muscles, i.e., quadriceps, hamstrings, gluteus, plantar flexors 4 exercises: each 5 min/day 7 days/week |
Contraction type: isometric in leg press Control condition: separate passive control group and contralateral control leg |
MVC + 4.4% |
| Worrell et al. [135] | n = 19 | 3 weeks |
Hamstrings 4 × 15–20 s/day 5 days/week |
Contraction type: isokinetic at 60°/sec and 120°/sec Control condition: uncontrolled |
Eccentric peak torque 60°/sec + 8.5%, eccentric peak torque 120°/sec + 13.5%, concentric peak torque 120°/sec + 11.2%, no significant increase for concentric peak torque 60°/sec |
| Yahata et al. [38] | n = 16 | 5 weeks |
Plantar flexors 6 × 5 min/day 2 days/week |
Contraction type: isokinetic at 30°/sec and 120°/sec and isometric at 30° plantar flexion and neutral Control condition: contralateral control leg |
MVC isometric with neutral ankle angle + 6.4 MVC isokinetic at 120°/sec + 7.8% Other tests showed no significant changes |
1RM one repetition maximum, ES electrical stimulation, IG Intervention group, min minutes, MVC maximal voluntary contraction, MVIC maximal voluntary isometric contraction, n number of participants, sec seconds
aBecause of inconsistency in reporting, the % change is only stated as the mean value