Table 4.  Evidence for motor unit synchronisation.
Author
Participants
Vibration
Method (type)
Exercise
Type
Frequency
(Hz)
Amplitude
(mm)
Duration
Results
Bosco et al., 1999a
12 national boxers
DB
Elbow Flexion
260
60
5 x 60 s5 x 60 s
During vibration %EMGrms significantly increased and elbow flexion power was significantly enhanced (14%) compared to no vibration.
Bosco et al., 1999b
6 AT
SV
Control
SS SS
260
100
10 x 60s 10 x 60s
Leg press velocity-force and power-force relationship shifted to the right after vibration
Bosco et al., 2000
14 RA
SV
Standing, SS, lunge
26
10
5 x 90 s, 10 days
Vibration increased leg press power (160% of body mass) by 7% and EMG/Power ratio significantly decreased
Delecluse et al., 2003
18 UT
19 UT
18 UT
VV
Placebo
Resistance
DS, SS, lunge
DS, SS, lunge
Cardio +knee
& leg extensor strength
35-40
Low
Cardio (20mins)
20RM (2wks),
15RM (3wks),
12RM (3wks),
10RM (4wks)
2.5-5
Low
1-3 x 2-6 x30-60 s
(3x/wk,
12 wks)
There was a significant increase in isometric and dynamic knee extensor strength for vibration and resistance groups but there was no significant difference between the two groups. Vibration increased EMG activity in rectus femoris and medial gastrocnemius compared to placebo group.
19 UT
Control
No training
NA
NA
Martin and Park, 1997
10 H
Direct vibration
Isometric
hand grip
40, 80, 100, 120, 150, 200 at 0,
10 or 20% MVC
0.2-0.3
60 s
Vibration frequency of greater than 150 Hz induced less motor unit synchronisation. When vibration increases subharmonic  synchronisation increases but harmonic synchronisation decreases.
RA = Recreationally active; H = Healthy; AT = Athletes; UT = Untrained DB = Dumbbell; SV= Side alternating vibration; VV = Vertical vibration; DS= Dynamic squat; SS = Static squat; MVC = Maximal voluntary contraction; NA= Not applicable; RM = Repetition maximum