written by, Mood
It appears that the Niners players in the ShanaLynch regime are having an unusually high incidence of soft tissue injuries.
The mechanism is clear -- Newton's laws and limits to tensile strength and flexural rigidity of tendons and ligaments. It's known that repetitive use, combined with overuse and microtrauma, may cause a progressive attrition of tendons. Wilson's meniscus did not rupture from standing up in the training room. His transferring his weight to his legs that involved a damaged meniscus was likely the final straw that broke the camel's back, so to speak.
If the answer was simple as better stretching, training and equipment, sports science would have had a clear answer by now. On the contrary, every major study has shown that stretching does not reduce injuries:
Strength training, etc., can strengthen tendons and ligaments to a limited degree but 200+lb men moving at 4.4 speed creates huge stresses. No health and training staff can help prevent such injuries because they cannot change the laws of physics. As the sports doctor David Chao has stated, it's easy to blame medical but many factors in injury from player selection, pre-existing injury, style of play, scheme, fatigue, playing conditions and of course bad luck are in play.
I've an unproven hypothesis in this regard. The root cause of this problem may be the kind of players ShanaLynch has recruited. They have placed a premium on creating a team of large, powerful players who play very fast. Such players, whether in contact or non-contact situations, place excessive stresses on their ligaments and tendons when they change directions sharply because of the massive accelerations involved for such large masses, which in turn imposes very large forces (and thus, large stresses) on the tendons and ligaments. Either players have to be large and slow, or small and fast, to reduce these stresses that may otherwise cause the tears.
However, I should clarify that I am not referring to the straight-line speed of large humans like Seattle's Metcalfe. I'm also strictly discussing soft tissue injuries, not bone injuries and concussions.
Instead I am referring to large humans changing directions sharply at medium to high speeds that put large torques on all musculoskeletal parts of the body, including the tendons and ligaments.
These sharp lateral movements causing high accelerations and high rotational stresses are more frequent in zone running schemes and in the Niners’ defensive philosophy of "all gas no brakes".
Consider the Wide 9 rush vs. the bull rush. In the wide 9, the rusher (Bosa, Ford) is running in a curve to avoid the tackle on the way to the QB -- constantly changing direction while traveling at high speeds (to cover greater distance to QB). Thus the rusher in wide 9 rush is acceleration at all points during the rush over longer distances putting extra rotational load on their tendons and ligaments compared to DEs coming off stunts where movements are in smaller spaces and the changes of direction are happening at lower speeds.
Also consider how the safety play has changed from the Lott - Lynch approach through visualizing running violently through the players, to the Tartt - Moore sideline-to-sideline mobility and running around defenders. These motions involve high rotational acceleration motions that may slowly wear down and degrade tendons and ligaments unless there is enough opportunity for rejuvenation.
It would be an interesting idea to look for correlations. For example, calculate a relevant metric for each player, e.g., ratio of weight to the product of 20 yard short-shuttle time and three-cone times.
Risk = weight / (short-shuttle time X three-cone time)
A larger number means higher risk of injury. Now take the average over the entire 53 and plot against such injuries per season.
These are just idle speculations. However, I expect that we will learn more about these injuries and their causes over the next several years leveraging machine learning techniques on MRI images that may be able to spot changing morphology of these soft tissues and detect damage to the tissues resulting from regular play so that there may be interventions possible before such catastrophic events as tears.