Whenever someone glowingly encourages you to use PRODUCT X which Stimulates fibroblasts (ie scar cells) to deposit collagen, in effect they are saying, that Product X causes an injury to the skin which cases fibroblast scar cells to react and produce a mild, scar-like collagen formation. With time, this collagen is either broken down completely or is replaced with other mature collagen. Injury = Collagen deposition. Greater injury = greater Collagen deposition = scar tissue. The key with all such treatments is to not over-do the injury to prevent scar formation.
Often times it is not how strong you are when you are fresh but how strong you remain once you become winded and have expended a lot of energy that determines the outcome. In a martial arts or fighting context, “enduring strength” is a very important skill. Maximal strength is very important as well, but the well rounded fighter must be prepared to deliver multiple strikes in combinations. This requires tremendous strength/endurance. Kettlebell high repetition snatches, for example, develops a strong work capacity and anaerobic threshold.