Long-term whole-body vibration training in two late-onset Pompe disease patients

The treatment of late-onset Pompe disease (LOPD) relies on enzyme replacement therapy (ERT) and physiotherapy but the most appropriate exercise program is not yet established. Whole-body vibration training (WBVT) has showed promising results, improving motor performances in various populations. Our aim is to assess the effects of WBVT performed by two LOPD patients in addition to ERT and physiotherapy. A side-alternating WBVT lasting 2 years; clinical assessments included: manual muscle testing (MRC sumscore), knee extension and arm flection isometric strength (multi-muscle tester M3diagnos), timed function tests (10 m walking, standing-up from chair, ascending 4-steps), 6 min walking (6 MWT), motor disability (Walton Gardner-Medwin scale), pulmonary function. Follow-up evaluations performed for 9 years since ERT start (pre-WBVT and post-WBVT) are reported for comparison. MRC sumscore improved in both patients (Pt.1:41 → 48, Pt.2:42 → 47) as isometric strength of knee extension (Pt.1: + 62 %, Pt.2: + 26 %) and arm flection (Pt.1: + 88 %, Pt.2: + 66 %), 6 MWT improved in Pt.1 (+75 m). Timed function tests did not greatly change. Patients reported no significant CK elevation or WBVT-related complaints. WBVT may be safely used in LOPD and seems to moderately boost muscle strength in patients receiving ERT and physiotherapy for more than 3 years. Larger cohorts should be studied to better assess WBVT potential as adjunctive exercise tool in LOPD.

Acute whole-body vibration reduces post-activation depression in the triceps surae muscle

PURPOSE

Acute whole-body vibration (WBV) is known to enhance neuromuscular activation. Especially mechanisms which act presynaptically are discussed to be involved in this modulation, but evidence is still limited. Therefore, this study aimed to investigate if 2 min of WBV might impact the premotoneuronal mechanism of post-activation depression (PAD).

METHODS

PAD in m. soleus was assessed by paired-pulse stimulation in 28 healthy participants prior, 2 min, 4 min and 10 min after 2 min of side-alternating WBV (10 Hz, 2 mm). Methodologies involved electromyography (m. soleus, m. tibialis anterior) and goniometric recordings (ankle, knee joint). H-reflexes were elicited with peripheral nerve stimulation and assessed by means of conditioned H-reflexes (ISI 1 s, H_cond) versus control H-reflexes (ISI₁₀, H).

RESULTS

H_cond/H was significantly enhanced by +55% (2 min), +32% (4 min) and +35% (10 min) following WBV (P < 0.05). Baseline muscle activity and joint positions were shown to be reliable (Cronbach's α values >0.990) throughout the testing procedure.

CONCLUSION

Vibratory-induced spinal inhibition is accompanied by diminished PAD at the presynaptic terminals which interconnect the Ia afferents with the α-motoneuron. Functionally, the PAD reduction might explain enhanced motor performance following vibration therapy, but future studies will be needed to verify this assumption.