Previously we reported how a team of leading Danish and Swedish researchers were able to maintain muscle/tendon integrity of postural muscles in men subjected to 90-day bed-rest, which induces muscle loss amounting to 25% or even more. The prescription: YoYoTM Supine Squats every third day! Without any exercise preventing this marked muscle atrophy, the additional stress on collagen tissue, and hence tendons would have been substantial.
Recently, researchers (picture shows first author Fernando Sanz-Lopez, now with Aspetar and the Qatar Handball Federation) from Universidad San Jorge, Zaragoza and Universidad de Jaén in Spain investigated runners who had performed 4 sets of 7 reps on the YoYo Squat twice weekly for six weeks. The research team then measured the changes in Achilles tendon size and the gastrocnemius muscle pennation angle.
They reported major changes in architecture of the calf muscle and tendon thickness. These changes should benefit performance and make runners less vulnerable to injury!
Sanz-López F, Berzosa Sánchez C, Hita-Contreras F, Cruz-Diaz D, Martínez-Amat A. Ultrasound Changes in Achilles Tendon and Gastrocnemius Medialis Muscle on Squat Eccentric Overload and Running Performance. J Strength Cond Res. 2016 Jul;30(7):2010-8. doi: 10.1519/JSC.0000000000001298.