just need soem advice, whenever i squat my knee's seem to bend inwards, i know this is a sign of weekness, but it is even evident on lighter lifts to, could it be my stance or just serious lack of leg training,or possibly since i more so focused on upper body for the first year of training?
Dave Tate talked about this at the Tate/Defranco seminar. He said to sit on a low box (maybe 4 inches off the ground), wrap a band around your knees and do sets of 10-15 reps bringing your knees apart. Hold at the peak contraction for 4 seconds.
You could also have tight muscles (primarily inner thighs) and like you mentioned your stance might be wrong for you. I have long legs and do best with a very wide stance. If you have shorter legs then try bringing in your feet and see how that feels.
What you have is a weakness of your gluteus medius muscle. This muscle when properly strengthened will prevent the femur from internally rotating ie. keep your knees from buckling inward. The above poster got it right. You can also isolate each glut. med. by taking the band and putting it around your knees and then lying down on your left or right side with your knees flexed at about 90 degrees and your hips flexed to 45 degrees (think almost fetal position). Keep your top foot in contact with the bottom foot and then spread (or lift) your top knee away from the knee on the table. Depending on the strength of the band you can do anywhere from 3x10 to 4x20. on each side. In addition, if your gym has a 4-way hip machine it wouldn't hurt to add some hip extension and abduction work in as well.
Sounds as if you need to strengthen your adductors. If you don't have access to a machine, you can use wide stance squats using lighter weight for a couple of sets after your work sets or a couple of sets of 20 of adductor machine work.
There appears to be several weaknesses and overactivity in the lumbar-hip-knee-ankle complexes.
Tightnesses: 1. Adductors 2. Semitendinosus, Semimembranosus 3. Illiacus 4. IT Band 5. Medial Gastrocnemius, Soleus 6. Peroneus 7. Posterior Tibialis
Weaknesses: 1. Glute Medius, Minimus 2. Piriformis 3. TFL 4. Bicep Femoris, long head 5. VMO 6. Satorius
Search T-Nation for articles on strengthening your weaknesses and flexibility methods for the tight areas. You may also seek a physical therapist who can give you a R.O.M. test of the aforementioned joints to verify these areas to be impacted by muscle imbalances.