I have used papain with some marinades for goat meat. Personally I do not care much for marinades any more, at least not long ones. For example, I used to marinate chicken overnight with spices and yogurt when making chicken tikka or tandoori chicken.
1 Pain at the base of the spine causes the psoas muscle to shorten and weaken(1,2,3,). 2  80% of Western people will suffer from debilitating backpain some time in their lives(5).  Western style walking (comfortable shoes & flat ground) fails to trigger muscles that stabilize hip joints & lower back.
The muscles of the back are connected to the spine by strong tendons. The upper back is covered by the trapezius muscle, the rhomboids (major and minor), and the teres major. The mid portion of the back is covered by the large latissimus dorsi muscle. The erector spinae group attaches to and supports the spinal column.