Week 11

Response 1: Josh Young

When I was in high school, I tore my ACL playing basketball. Since then, I have been interested in ACL injuries and rehab techniques, so this article really hit home with me. What interested me the most was how the loads on the ACL, and PCL too, could be measured. I was shocked to learn that in healthy adults, the native ACL could handle roughly 2000 N of force (Escamilla, MacLeod, Wilk, Paulos, & Andrews, 2012). That comes out to roughly 450 pounds! That is a lot of force that the ACL can handle. It makes sense though that the ACL would need to withstand that amount of force because of the importance of knee stabilization in daily activities. Another thing that I found interesting was where in the knee’s range of motion the ACL and PCL were loaded the most. The ACL is loaded the most at knee angles less than 30 degrees and the least at angles between 50 and 100 degrees (Escamilla et al., 2012). In other words, the ACL is loaded most near full knee extension, with the load decreasing as the knee is flexed. The PCL is just the opposite. It is loaded more when the knee is flexed and less as the knee is extended. The way these two ligaments work together is amazing. As one ligament is loaded, the other is unloaded. Lastly, I thought the discussion about the rehab exercises was particularly interesting. It was found that, in general, weight bearing exercises (WBEs) produced a smaller load on the ACL and PCL compared to non-weight bearing exercises (NWBEs) (Escamilla et al., 2012). I thought back to when I was rehabbing my knee. My therapist had me performing WBEs and NWBEs. At the time, I didn’t notice a difference, but looking back, I remember preferring the WBEs over the NWBEs. The NWBEs, specifically the seated knee extension and the prone hamstring, did seem to aggravate my knees more than the WBEs did. Before reading this article, I was not a fan of the seated leg extension machine. I felt like it put too much stress on the knees, and that the benefits did not outweigh the risks of long-term damage to the knees. Instead, I would opt for closed chain, WBE to strengthen the quads, like squats or lunges. The article even says that the seated leg extension machine puts significantly greater stress on the ACL than WBEs (Escamilla et al., 2012), which, after reading the rest of the article, does not surprise me. Plus, I like to have my feet, and patients’ feet too, on the ground when strengthening the legs. That is more functional and can be transferred across any activity or sport. 

Response 2: Delania Adams

After reading the article, "Biomechanics of the Ageing Foot and Ankle: A Mini-Review" I found some of the information to be very informative as well as interesting. Some risk factors for foot pain result in increased age, female sex, obesity, chronic conditions, osteoarthritis and diabetes, and inappropriate footwear (Menz, 2014). One thing I can say that I've had experience with is the correlation between inappropriate shoes contributing to ageing foot and ankle. It is imperative to wear the proper footwear, as it can lead to other things such as poor posture, hip, and knee replacements. One thing that I was not familiar with was age-related changes in the skin. The plantar skin has several unique features which relate to the biomechanical demands of weight bearing (Menz, 2014). The dermis is 3mm thick, and is penetrated by adipose tissue which provides resilience to shear stress (Menz, 2014). Hyperkeratosis is a continuing issue in elderly people, this is caused by flattening of the dermo-epidermal junction (Menz, 2014). Another thing that caught my eye pertaining to age-related changes in range of motion pertaining to changes In the body. Joint changes can included, reduction in the water content of the cartilage, the synovial fluid volume and the proteoglycans (Menz, 2014). Collagen fibers within the cartilage causes cross-linking process that results in increased stiffness, changes can contribute to a reduced range of motion in lower extremity joints in most elderly people (Menz, 2014). I also learned from this article the correlation between age-related changes in foot posture and dynamic foot function. The medial longitudinal arch of the foot plays an important role in shock and begins to generate sufficient power for propulsion when walking (Menz, 2014). It is extremely important for elderly people to wear the correct shoes as their posture begins to cause more pressure on their body with a combination of gravity contributing to the weight bearing burden. After reading this article I have learned a lot of great things that I can now tell my patients who are now experiencing trouble with foot and ankle issues. This article will allow me to come up with better rehabilitation solutions for my patients.

Response 3: Kendra Clamors

     I have never really had a problem when it came to my knees when playing soccer through out high school and college. I always heard about women tearing their ACL’s, MCL’s, and PCL’s, hoping that it would never happen to me. With working at the physical therapy clinic that I do, we don’t see many people coming through with those kinds of tears for some reason. Cruciate ligament injuries are common and may lead to dysfunction if not rehabilitated. Understanding how to progress anterior cruciate ligament and posterior cruciate ligament loading, early after injury or reconstruction, helps clinicians prescribe rehabilitation exercises in a safe manner to enhance recovery. Commonly prescribed therapeutic exercises include both weight-bearing exercise and non-weight-bearing exercise (Escamilla et al., 2012). What was interesting to me in this article is when they talked about the in vivo and experimental biomechanical models used to evaluate ACL strains or tensile force during weight-bearing exercises and non-weight-bearing exercises. The obvious advantage of in vivo studies is that they calculate ACL strain directly by using strain sensors within the ACL. There are several limitations to measuring ACL strain in vivo, such as, the procedure is invasive, time consuming, costly, performed in a patient population under surgical conditions, and that the types of activities are limited (Escamilla et al., 2012). The advantage of using experimental models is that the estimated loads are better generalized to the active athletic population because variables are often better controlled. The obvious limitation of experimental biomechanical knee models is that they do not measure ACL loading directly, but only estimate its value (Escamilla et al., 2012). Early after injury or reconstruction of the cruciate ligament the clinician should prescribe WBE rather than NWBE, and progress to NWBE as tolerated and to facilitate isolated muscle functional groups – such as the quadriceps (Escamilla et al., 2012). The findings of this article were kind of expected. The ACL is loaded less at higher knee angles (i.e. 50–100). Squatting and lunging with a more forward trunk tilt and moving the resistance pad proximally on the leg during the seated knee extension unloads the ACL. The PCL is less loaded at lower knee angles (i.e. 0–50) and may be progressed from level ground walking to a one-leg squat, lunges, wall squat, leg press, and the two-leg squat (Escamilla et al., 2012).

Response 4: Chad Rawdon

When we are born we learn to control our bodies from head to toe and as we age we typically start having less control from our starting with our lower extremities. As Menz shares, foot pain affects approximately one in four older people and is associated with a decreased ability to undertake the activities of daily living, problems with balance and gait and poorer health-related quality of life. (Menz, 2014). These are issues which need addressed since we are living longer lives, the need for pain free mobility after retirement is becoming more and more important. Everything in our body eventually “wears out”, so the changes in the skin and the tissues were not that surprising to me. What I did find interesting was that ankle dorsiflexion, plantarflexion, and subtalar joint inversion-eversion range of motion are 12–30% lower in older people and older people were found to have 32% less dorsiflexion range of motion of the first metatarsophalangeal joint than younger people. (Menz, 2014) With these numbers I would like to know a little more of the background of the individuals taking part in the studies, did they work jobs that were on their feet often, were they up and down on their hands and knees and standing all day or were they in more sedentary activities. My mother had to have surgery on her feet after her retirement from teaching for 35 years. Early in her career she would dress professionally, dress clothes and dress shoes, later in her career she started to wear tennis shoes and really helped her alleviate the pain in her feet from the poor support of dress shoes. She has always been active and quit playing soccer in her 50’s but kept lifting, running/walking, and swimming to this day and after her surgery has been pain free for the most part as long as she doesn’t overdo it at her back to back body pump and boot camp classes. Judging from my mother and others that I have known through the years I would say that as long as you are active and keep using your lower limbs for challenging activities you can stay in the 75% who don’t have foot pain. I have said it before the body is an efficient machine, it will keep running strong if you take care of it and don’t let it sit for too long.

Response 5: Thomas Ellis

The second article I thought was really interesting and something I could relate to. My dad is going to be 61 this year and has had ankle issues for the longest time, ever since I was in high school and it has progressively gotten worse over the past few years. Genetics has made his ankles along with other men in his family very weak ankles. His ankle joint sits sort of off on his foot. What I mean is that he is basically severely pronated and walks with a sort of duck walk. As Menz (2014) mentions, as ankles get older, the ability to do activities of daily living, balance and walk can decrease. I thought it was interesting that Menz (2014) talked about the tissues of the bottom of the foot. I know from a previous biomechanics class that the hardest bone in the body is the calcaneous or our heel. There is also a lot of force dissipated across the foot whenever we do walk everyday. Menz (2014) mentions that some of the pain that comes in the aging ankle is the first layer of tissue, that normally absorbs the impact when walking, deteriorating over time and then falls into the deeper tissues to absorb. I have also had a client that has come to me with ankle issues. I notice when she tries to squat that her knees crash but she also has a very limited range of motion. The biggest thing I always ask her is does her ankle hurt when she tries to squat and she says yes. Well I tried to see where ankle mobility was and her plantarflexion and dorsiflexion was not very good. She said she had some pain in her everyday life just walking around so this article I found expanded my knowledge about the topic. After reading about the different ways to redistribute pressure around the foot I think that insoles would be best for any aging individual that experiences ankle pain. Menz (2014) talks about making sure the pressure distributes to the medial arch and I think that is where some insoles can come into play because they can adjust the arch in a persons foot. Some people have low arches and others no arch so making an arch for them could help to reduce the ankle pain they experience.