Bending down or plié is one of the crux of dance and simply movement. It requires one very special joint in our bodies to work well for us to feel functionally okay, to simply achieve the once and still evolutionary marvel of being human, the ability to walk upright. The one special joint—the knee joint.
...one very special joint in our bodies to work well for us to feel functionally okay, to simply achieve the once and still evolutionary marvel of being human, the ability to walk upright. The one special joint—the knee joint.
The knee joint is a hinge joint that could only move on one plane. Meaning it could only be bent or straightened, but not moved from side to side or in circular motion. It also bears the weight of our bodies and connects it to the foot that works to bring us around in space, be it within or outside of the dance setting.
1. What is the knee composed of?
The knee is part of our skeletal system. Which consists of:
Bones
That is the frame of the body and its parts.
Patella is the fancy latin name for knee cap that is the “face” of the knee joint.
If you ever knelt or fell on your knee, and got away with some bruises and or scratches on the skin, your sweet ol' patella is working perfectly well to protect the gap between you femur (thigh) and tibia (calf).
Joints
A gap between the bones that allow space for movement of the knee.
The wider the space, the wider the range of motion one possess, or what we call mobility/flexibility.
Hyperextension of the knee is a sign or hint that one has above average range of motion.
Quick Assessment on knee hyperextension:
Seated with feet stretched in front of the body in parallel. When your knees are fully stretched, if your heels come off the floor, you have hyperextension to different degrees. 
Ligaments
The official and proven natural strong adhesives for bones that connect one bone to another forming the frame of the body or its parts, just like our knee here.
There are adhesives all around the knee joint to stabilise the gap for efficient bend (flexion) and stretch (extension) movement.
2. Where is the knee located in relation to the body?
Above the knee
Connecting from the knee up, is our thigh bone, or femur, the longest bone of the body that is usually used in movies as probs to scare people indicating the darker side of life.
Below the knee
Connecting from the knee down, is the tibia and fibula
With such strong and long bones, not to mention muscles, sitting atop and below the knee joint, how does the knee take the impacts? Let’s find out at number #3.
3. How does the knee hold the upper and lower legs together while allowing movement?
The HINGE with screws (ligaments) that connect two “parts” (or bones) together.
Think of it this way, the knee is the hinge you got from your new Ikea cabinet with a door. And in order to piece the door (tibia) to the cabinet (femur), you need to use the hinge (knee joint) screwed tight (by ligaments around hinge/knee) to the edges of the two parts. And voila, you got your brand new door on the cabinet that moves just like your knee, opens and closes; bends (flex) and stretches (extend).
4. How does the hinge or knee joint stay smooth and impact resistant?
To allow your legs to bend and stretch without hindrance, besides the soft bones (cartilages) at the ends of the connecting bones (femur, tibia, and patella), the joint capsule of the knee have cushions in solid and liquid at strategic locations that absorb the impacts and keep it lubricated, they are the:
Meniscus/menisci—c-shaped cartilages (there are two, one on each side of your knee) between femur and tibia for extra cushioning, preventing wear and tear of the bones.
Bursae/Bursa—fluid filled sacs. The squishy part of your knee you can feel.
Synovial fluid—your ultimate knee grease secreted by synovial membrane
Now that we know what we are dealing with, we can now look at the examples of the kinds of movement the knee creates in our daily life and in dance.
5. Knees in static and in motion.
Example of the knees in action during a dance class, rehearsal or performance:
Static
The knee is held in space and time without motion either flexed or extended
Standing, turning or holding in positions as if trying to stay for a moment to be captured on camera or screen.
In motion
The knees are flexed and extended based on the temporal and spatial requirement of a specific dance routine.
Travelling or linking steps, e.g. walking, running, jumping.
6. How to move wisely with the knee?
You should have noticed by now that the knee can only open or close like the door, which we call, a hinge joint— a joint that can only move in one plane of motion. So, we can essentially create only two movements at the knee joint:
Bend—flexion
Stretch—extension
What makes the joint so fragile when it comes to dance is the shifting of the skeletal frame that sits above and below the knee in complex combination in time and space. When we dance, the dynamic changes in our bodies create constant stress on the joint. The physics that are involved in movement or dance is so complex that when anticipated, the muscles will fire up signals to the brain which can decide in an instant to send how much energy, force or strength to support the movement created. When the physical and the neural pathways (technique) are not strong enough (yet!) to anticipate the movement, what tends to happen are—injuries.
7. Common injuries to the knees
“Ouch, my knee hurts!”
Happens to the best of us. What we need to know is where and why it hurts to know how to prevent further pain. Just like a hinge that will rust and eventually lose its ability to open and close like a door. The knee joint is susceptible to wear and tear over time. Most knee injuries in dance are caused by overuse. We already know what the knee is composed of to be able to identify where and how to manage the injury to the knees. But of course, if your pain persists, always seek qualified professional help.
Here is how you could better describe your pain to get a proper diagnosis and the right treatment along with some common injuries in dance.
8. How to strengthen the knee?
Nutrition
Since wear and tear is something unavoidable, the only way to slow down the ageing process is to eat well. Eat a well balanced diet to ensure that your body have adequate and suitable sources of the below nutrients to maintain and keep your bones and ligaments strong.
Energy—calories from whole or natural foods (calculate your daily calorie requirement here).
Essential amino acids—from animal or plant protein.
Vitamins and minerals—particularly Calcium and Vitamin D for your bones; and magnesium to regulate metabolic functions to maintain your body's natural power to recover and heal.
NOTE: Be sure to diversify your plant-based protein and supplement with Vitamin B12 to ensure you get all the nine essential amino acids and vitamins you need through your diet. Track and check the origin of your animal protein. As much as you can, know where your food come from. As we all hear it too often, that "you are what you eat". Stay informed on ethical and sustainable food sources from your local communities or local Facebook groups for nearby farms and grocers. Conditioning Training
Generally speaking, dancers do not need to be told how to stretch, or when to stretch as most dancers (not all) are constantly stretching. Rather, are you balancing your stretching with strength training? If no, this mantra is especially for you: "Strengthen not stretch!".
The knee is surrounded by bones and ligaments that help support and optimise the hinging motion (flex and extend). What we should aim to do, is to balance stretching and strengthening of the muscles that are attached to the joint via tendons above and below the knee. A tip, at Tarinao, we encourage not only working on the body parts, but also working on your mind and awareness—the bio-psycho aspect. Meaning, half of the work is in the working of your mind, making sure that you have a complete understanding of the technique while performing the technique itself, simultaneously.
Above the knee
Here along with many other exercises you can try that you may find from reliable resources online. The bottom line is to balance work on all sides of the thigh. Also make sure that the quality and quantity of time and effort spent on both stretching and strengthening exercises are balanced, for example:
Front back (Quadriceps and hamstring)
Squats
Lunges
Quadriceps stretch
Hamstrings stretch
Side (Iliotibial band)
Iliotibial band release
Below the knee
Calf rises
Calf stretch
Time is a key in deciding what we prioritise in today's very busy world. It can sometimes feel impossible to squeeze in some time for conditioning exercises. But, if you have no extra time dedicated to conditioning exercises, for example, when you do your plié or simply bending down to pick something up, pay attention (be more mindful) to how similar it is to squats and think about your front and back thigh muscles working. The technique when applied in daily life as part of your movement habits can be just as strong if not stronger than doing conditioning exercises mindlessly. Something is always better than nothing.
We do hope with these 8 things to know about your knees, you can dance with higher freedom and enjoyment. Being more empowered with the knowledge to protect your knee and dance with no fear of buckling the knee. Have fun moving with improved technical comprehension (only bend and stretch the knee in strong sense of alignment—knee in line with second toe!) and don't forget to build stamina and strength on the muscles around the knees.
Disclaimer
It is not intended to be a substitute for professional medical advice and should not be relied on as health or personal advice. Always seek the guidance of your doctor or other qualified health professional with any questions you may have regarding your health or a medical condition.
References
Calmbach, W. L., & Hutchens, M. (2003). Evaluation of patients presenting with knee pain: Part I. History, physical examination, radiographs, and laboratory tests. American family physician, 68(5), 907-912.
Calmbach, W. L., & Hutchens, M. (2003). Evaluation of patients presenting with knee pain: Part II. Differential diagnosis. American family physician, 68(5), 917-922.
Hoffman, M. (2021). Picture of the knee. WebMD. Retrieved 17 June 2021, from https://www.webmd.com/pain-management/knee-pain/picture-of-the-knee.
Knee Capsule Strains. Jacksonville Orthopaedic Institute. (2021). Retrieved 17 June 2021, from https://www.joionline.net/trending/content/knee-capsule-strains.
Lindberg, S. (2019). Exercises for Knee Pain: 10 Exercises for Pain Relief. Healthline. Retrieved 24 June 2021, from https://www.healthline.com/health/exercises-for-knee-pain.
Taylor, T. (2019). Knee Joint. Innerbody Research. Retrieved 17 June 2021, from https://www.innerbody.com/image/skel16.html.