Progressive overload refers to the deliberate, gradual increase in stress placed on the body in order to facilitate an adaptive process by which your tissues change structurally and functionally to be able to meet the demands of greater and greater loads.
In order for this adaptation to take place, loads must be adequate and consistent. If you are a yogi and/or are hypermobile you may have suffered from symptoms colloquially known as ‘yoga butt’ a nagging feeling of pain directly at the sit bone. This symptom may be the result of hamstring tendinopathy – degradation of the hamstring tendons in the form of micro-tears. Passive stretching will not this sit(bone)uation better. If fact, it may be what caused it.
In a practice like yoga asana, the hamstrings are often subjected consistently to low tensile loads, as in passive stretching. These low tensile loads are not adequate enough to result in the laying down of more collagen for increased density and strength of the hamstring tendons. This doesn’t mean passively stretching the hamstrings is wrong or bad. It simply means that it is an incomplete or inadequate ‘load diet’ for facilitating their musculoskeletal health. This video offers a few ways in which you could begin to externally load – and over time progressively overload – this muscle group in both concentric and eccentric phases of contraction to facilitate improved tendon health.
Adding external load could, over time, facilitate a positive adaptive process by which your hamstring tendons get stronger. They quite literally – in terms of physics – get stiffer. Don’t confuse physics jargon for the layman’s use of the word stiff. They are not the same. Your tendons can (and want to be) stiff and flexible! Their increased stiffness will equate to more resilience to tears and micro-tear injuries.