Complex sentence: Advocates of the Alexander Technique make claims for its treatment potential for a variety of conditions but evidence was of low to moderate quality and overall, the effectiveness of the Alexander Technique is uncertain because of insufficient evidence.
Split into simpler sentences: Advocates of the Alexander Technique also make claims that it has treatment potential for a variety of health conditions. However,, supporting medical evidence was of low to moderate quality and overall, the effectiveness of the Alexander Technique is uncertain because of insufficient evidence.