Weight bearing through lower limbs in a standing frame with and without arm support and low-magnitude whole-body vibration in men and women with complete motor paraplegia
date: 2012 Apr;91(4):300-8. doi
author: Bernhardt KA
publication: Am J Phys Med Rehabil
The aim of the study was to determine the proportion of body weight borne through the lower limbs in persons with complete motor paraplegia using a standing frame, with and without the support of their arms. We also examined the effect of low-magnitude whole-body vibration on loads borne by the lower limbs.
Vertical ground reaction forces (GRFs) were measured in 11 participants (six men and five women) with paraplegia of traumatic origin (injury level T3-T12) standing on a low-magnitude vibrating plate using a standing frame. GRFs were measured in four conditions: (1) no vibration with arms on standing frame tray, (2) no vibration with arms at side, (3) vibration with arms on tray, and (4) vibration with arms at side.
GRF with arms on tray, without vibration, was 0.76 ± 0.07 body weight. With arms at the side, GRF increased to 0.85 ± 0.12 body weight. With vibration, mean GRF did not significantly differ from no-vibration conditions for either arm positions. Oscillation of GRF with vibration was significantly different from no-vibration conditions (P < 0.001) but similar in both arm positions.
Men and women with paraplegia using a standing frame bear most of their weight through their lower limbs. Supporting their arms on the tray reduces the GRF by approximately 10% body weight. Low-magnitude vibration provided additional oscillation of the load-bearing forces and was proportionally similar regardless of arm position.
The osteogenic potential of short durations of low-level mechanical stimuli was examined in children with disabling conditions. The mean change in tibia vTBMD was +6.3% in the intervention group compared with -11.9% in the control group. This pilot randomized controlled trial provides preliminary evidence that low-level mechanical stimuli represent a noninvasive, non-pharmacological treatment of low BMD in children with disabling conditions.
Recent animal studies have demonstrated the anabolic potential of low–magnitude, high-frequency mechanical stimuli to the trabecular bone of weight-bearing regions of the skeleton. The main aim of this prospective, double-blind, randomized placebo-controlled pilot trial (RCT) was to examine whether these signals could effectively increase tibial and spinal volumetric trabecular BMD (vTBMD; mg/ml) in children with disabling conditions.
MATERIALS AND METHODS:
Twenty pre-or postpubertal disabled, ambulant, children (14 males, 6 females; mean age, 9.1 +/- 4.3 years; range, 4-19 years) were randomized to standing on active (n = 10; 0.3g, 90 Hz) or placebo (n = 10) devices for 10 minutes/day, 5 days/week for 6 months. The primary outcomes of the trial were proximal tibial and spinal (L2) vTBMD (mg/ml), measured using 3-D QCT. Posthoc analyses were performed to determine whether the treatment had an effect on diaphyseal cortical bone and muscle parameters.
RESULTS AND CONCLUSIONS:
Compliance was 44% (4.4 minutes per day), as determined by mean time on treatment (567.9 minutes) compared with expected time on treatment over the 6 months (1300 minutes). After 6 months, the mean change in proximal tibial vTBMD in children who stood on active devices was 6.27 mg/ml (+6.3%); in children who stood on placebo devices, vTBMD decreased by -9.45 mg/ml (-11.9%). Thus, the net benefit of treatment was +15.72 mg/ml (17.7%; p = 0.0033). In the spine, the net benefit of treatment, compared with placebo, was +6.72 mg/ml, (p = 0.14). Diaphyseal bone and muscle parameters did not show a response to treatment. The results of this pilot RCT have shown for the first time that low–magnitude, high-frequency mechanical stimuli are anabolic to trabecular bone in children, possibly by providing a surrogate for suppressed muscular activity in the disabled. Over the course of a longer treatment period, harnessing bone’s sensitivity to these stimuli may provide a non-pharmacological treatment for bone fragility in children.
In this 6-month trial, twenty children with cerebral palsy (age 6.2 to 12.3 years; 6 girls) were randomized to either continue their school physiotherapy program unchanged or to receive 9 minutes of side-alternating whole-body vibration (WBV; Vibraflex Home Edition II, Orthometrix Inc) per school day in addition to their school physiotherapy program. Patients who had received vibration therapy increased the average walking speed in the 10 m walk test by a median of 0.18 ms(-1) (from a baseline of 0.47 ms(-1)), whereas there was no change in the control group (P=0.03 for the group difference in walking speed change). No significant group differences were detected for changes in areal bone mineral density (aBMD) at the lumbar spine, but at the distal femoral diaphysis aBMD increased in controls and decreased in the WBV group (P=0.03 for the group difference in aBMD change). About 1% of the WBV treatment sessions were interrupted because the child complained of fatigue or pain. In conclusion, the WBV protocol used in this study appears to be safe in children with cerebral palsy and may improve mobility function but we did not detect a positive treatment effect on bone
Whole-body vibration training compared with resistance training: effect on spasticity, muscle strength and motor performance in adults with cerebral palsy.
The aim of this study was to evaluate the effect on spasticity, muscle strength and motor performance after 8 weeks of whole-body vibration training compared with resistance training in adults with cerebral palsy.
Fourteen persons with spastic diplegia (21-41 years) were randomized to intervention with either whole-body vibration training (n=7) or resistance training (n=7). Pre- and post-training measures of spasticity using the modified Ashworth scale, muscle strength using isokinetic dynamometry, walking ability using Six-Minute Walk Test, balance using Timed Up and Go test and gross motor performance using Gross Motor Function Measure were performed.
Spasticity decreased in knee extensors in the whole-body vibration group. Muscle strength increased in the resistance training group at the velocity 30 degrees /s and in both groups at 90 degrees /s. Six-Minute Walk Test and Timed Up and Go test did not change significantly. Gross Motor Function Measure increased in the whole-body vibration group.
These data suggest that an 8-week intervention of whole-body vibration training or resistance training can increase muscle strength, without negative effect on spasticity, in adults with cerebral palsy.
Whole-body vibration training is a method for muscle strengthening that is increasingly used in a variety of clinical situations. Key descriptors of vibration devices include the frequency, the amplitude, and the direction of the vibration movement. In a typical vibration session, the user stands on the device in a static position or performs dynamic movements. Most authors hypothesize that vibrations stimulate muscle spindles and alpha-motoneurons, which initiate a muscle contraction. An immediate effect of a non-exhausting vibration session is an increase in muscle power. Most studies of the longer term use of vibration treatment in various disorders have pursued three therapeutic aims: increasing muscle strength, improving balance, and increasing bone mass. In a small pilot trial in children we noted improvements in standing function, lumbar spine bone mineral density, tibial bone mass, and calf muscle cross-sectional area.
Effect of a new physiotherapy concept on bone mineral density, muscle force and gross motor function in children with bilateral cerebral palsy.
The purpose of this study was to determine the effect of a new physiotherapy concept on bone density, muscle force and motor function in bilateral spastic cerebral palsy children.
In a retrospective data analysis 78 children were analysed. The concept included whole body vibration, physiotherapy, resistance training and treadmill training. The concept is structured in two in-patient stays and two periods of three months home-based vibration training. Outcome measures were dual-energy x-ray absorption (DXA), Leonardo Tilt Table and a modified Gross Motor Function Measure before and after six months of training.
Percent changes were highly significant for bone mineral density, -content, muscle mass and significant for angle of verticalisation, muscle force and modified Gross Motor Function Measure after six months training.
The new physiotherapy concept had a significant effect on bone mineral density, muscle force and gross motor function in bilateral spastic cerebral palsy children. This implicates an amelioration in all International Classification of Functioning, Disability and Health levels. The study serves as a basis for future research on evidence based paediatric physiotherapy taking into account developmental implications.
The purpose of this study was to investigate the effects of whole–body vibration (WBV) on blood flow velocity and muscular activity after different vibration protocols in Friedreich’s ataxia (FA) patients. After two familiarization sessions ten patients received six 3 min WBV treatments depending on a combination of frequency (10, 20 or 30 Hz) and protocol (constant or fragmented). Femoral artery blood flow velocity, vastus lateralis (VL) and vastus medialis (VM) electromyography (EMG), and rate of perceived exertion were registered. Peak blood velocity was increased with respect to basal values after 1, 2 and 3 min of WBV (14·8%, 18·8% and 19·7%, respectively, P<0·001). Likewise, mean blood velocity was increased with respect to basal values after 1, 2 and 3 min of WBV (17·3%, 19·4% and 16·6%, respectively, P<0·001). EMG amplitude of VL and VM was increased (39% and 23%, respectively, P<0·05) and EMG frequencies decreased during the application of WBV. The results of this study suggest that higher frequencies (30 Hz) produce a greater increase in blood flow velocity and rate of perceived exertion. WBV is an effective method to increase blood flow and to activate muscle mass in patients with Friedreich’s ataxia, and could therefore be considered to be incorporated in rehabilitation programs of this collective.
author: van den Tillaar R.
publication: J Strength Cond Res. 2006 Feb;20(1):192-6.
Muscle strain is one of the most common injuries, resulting in a decreased range of motion (ROM) in this group of muscles. Systematic stretching over a period of time is needed to increase the ROM. The purpose of this study was to determine if whole-body vibration (WBV) training would have a positive effect on flexibility training (contract-release method) and thereby on the ROM of the hamstring musculature. In this study, 19 undergraduate students in physical education (12 women and 7 men, age 21.5 +/- 2.0 years) served as subjects and were randomly assigned to either a WBV group or a control group. Both groups stretched systematically 3 times per week for 4 weeks according to the contract-release method, which consists of a 5-second isometric contraction with each leg 3 times followed by 30 seconds of static stretching. Before each stretching exercise, the WBV group completed a WBV program consisting of standing in a squat position on the vibration platform with the knees bent 90 degrees on the Nemes Bosco system vibration platform (30 seconds at 28 Hz, 10-mm amplitude, 6 times per training session). The results show that both groups had a significant increase in hamstring flexibility. However, the WBV group showed a significantly larger increase (30%) in ROM than did the control group (14%). These results indicate that WBV training may have an extra positive effect on flexibility of the hamstrings when combined with the contract-release stretching method.
author: Cormie P, Deane RS, Triplett NT, McBride JM.
publication: J Strength Cond Res. 2006 May;20(2):257-61.
The purpose of this study was to investigate the effects of a single bout of whole-body vibration on isometric squat (IS) and countermovement jump (CMJ) performance. Nine moderately resistance-trained men were tested for peak force (PF) during the IS and jump height (JH) and peak power (PP) during the CMJ. Average integrated electromyography (IEMG) was measured from the vastus medialis, vastus lateralis, and biceps femoris muscles. Subjects performed the 2 treatment conditions, vibration or sham, in a randomized order. Subjects were tested for baseline performance variables in both the IS and CMJ, and were exposed to either a 30-second bout of whole-body vibration or sham intervention. Subjects were tested immediately following the vibration or sham treatment, as well as 5, 15, and 30 minutes posttreatment. Whole-body vibration resulted in a significantly higher (p < or = 0.05) JH during the CMJ immediately following vibration, as compared with the sham condition. No significant differences were observed in CMJ PP; PF during IS or IEMG of the vastus medialis, vastus lateralis, or biceps femoris during the CMJ; or IS between vibration and sham treatments. Whole-body vibration may be a potential warm-up procedure for increasing vertical JH. Future research is warranted addressing the influence of various protocols of whole-body vibration (i.e., duration, amplitude, frequency) on athletic performance.