Suffering from Low Back Pain? It could be "Sacroiliac Joint Dysfunction"

The Sacroiliac (SI) joint is the joint between your sacrum and your pelvis bone. The SI joints need to hold up the entire weight of the body, waist-up, and can have large amounts of stress on them with prolonged walking, standing and running. It is not a joint that moves as much as the hip or the spine, but it does have minute degrees of motion. Hence, it could "get stuck or jammed" from doing certain activities: landing on one leg too hard after a jump or leap, falling or landing a foot in a ditch while running, falling on one side of your hip. Prolonged, poor sitting posture (slouching!) can also cause it, as can pregnancy hormones and childbirth.
Here is what to look for:

•    One-sided pain in the buttocks and/or belt-line area
•    Aching or pinching pain at the SI joint
•    Pain worse with prolonged driving/sitting, prolonged standing. Pain is alleviated with walking/running/being active
•    Tightness and/or pain in low back muscles of the same side
•    Hamstring tenderness
•    Numbness/tingling sensations resulting from Sciatica

Here is what you can do:

•    Heat therapy if you feel that your muscles are tight and in spasm; place them around the area that feels tight
•    Cold pack therapy if you feel the joint is aching as this could be a result from inflammation
•    Avoid slouch-sitting and put a cushion at the small of your back for support (this could be done in the car also)
•    Sit up, stand and walk straight with good posture and avoid activities that involve stooping over (washing dishes, gardening) or leaning to one side while sitting (e.g. leaning on the center console in your car)
•    See your Physical Therapist if issues don't resolve

Here is how Physical Therapy can help you:

•    Manual therapy to correct joint alignment of the pelvis, and soft tissue massage to the muscles that are tense and in pain
•    Proper abdominal and hip strengthening exercises to make sure the corrected alignment stays
•    If the joint is inflamed, an anti-inflammatory patch is very helpful

•    Proper posture coaching so you don't continue to strain your SI joint

Knee Pain

Faulty Mechanics is a Common Side Effect and Cause

There are numerous diagnoses that explain for knee pain, e.g. patella tendonitis, chondromalacia patellae, IT Band syndrome, meniscus tear, ligamentous tears/laxity. Although differing in severity and presentation, they all result in one common thing: faulty biomechanics from weakened hip and quad muscles.

Non-traumatic knee pain tends to progress over time, and usually does not prompt the patient to seek immediate medical care for it. As a result of the pain, the body and brain shuts down usage of that limb and starts favoring the other stronger, healthier leg. The quads, glutes and peritibial muscles of the painful leg start to atrophy and surely enough, you start to see the biomechanical pattern above. Diagram A is of a person with good mechanics and strength doing a lunge; diagram B is what us PT's call "knee valgus" – the tendency for the knee to collapse inward because of weak hip abductor muscles, weak quads and excessive foot pronation. Faulty mechanics during daily activities will cause the knee pain to get worse regardless of its diagnosis. Knee pain begets more favoring of the leg … which begets more knee pain … and the cycle continues.

Those who are all too familiar with this may have tried the following interventions: rest; knee brace/strap; ice; IT Band foam rolling. Though this might help a bit in the short-term, the knee pain would most likely continue because you're not stopping the cycle.

The following is a better recipe for getting rid of the pain: supportive shoes or sometimes even orthotics (over-the-counter or prescribed by a podiatrist), quadriceps strengthening, gluteus medius and maximus strengthening, peritibial muscle strengthening, biomechanics retraining, manual therapy on the IT Band.
Yes, some knee injuries are severe enough that they do need surgical intervention. But oftentimes moderately severe knee pain is helped by biomechanics retraining and strength training by a good physical therapist.