A horse cannot be properly schooled if he is tense. The horse's muscles need to be relaxed before they can work thus before getting into ANY training program, the first and most important thing is to GET YOUR HORSE RELAXED AND WORKING COMFORTABLY in his surroundings.

A nervous rider will lead to a vicious circle and this circle will continue until things get out of hand and someone will get hurt.

Here are two photos. See if you can pick which photo is the photo where Elle is tense (as well as myself) and which one is where we're both relaxed:

If you chose the bottom one as us being relaxed, and the top one as us being tense, then you're abosultely correct. In the top one, note how Elle has a tense/hard neck and the muscle definition (in her tense rump) can be seen. Elle is NOT on the bit. She is also not tracking-up behind. Note the tension in the reins and stress put on the mouth. Me, as the rider from tightening up have began to lean forward and I'm not sure if it is terribly visible but my arms and hands are tight.

I can assure you, the bottom photo of Elle was much more comfortable to ride. She was relaxed with long flowing paces. Her neck is stretched longer and there is less tension in the reins and on the mouth. Muscle definition (from tightening) is not visible. My arms and hands appear softer.

If your horse is constantly like Elle is in the top photo, analyse your situation.

Ask yourself:
 

• How badly is my horse behaving?
• Am I the key to the problem? Am I anticipating my horse to be nervous (which automatically MAKES you nervous)? Am I constantly tense?
• What is my reason for being nervous (this is IF you're nervous)?
• What are my horse's reason(s) for being nervous
• Are there any particular things that might be upsetting my horse in the surroundings in which I handle/ride him?
• Is any of my gear pinching or hurting my horse?
• Is my horse genuinely scared or simply 'hot' (ie. full of energy)?- if he's 'hot', then is he receiving too much 'hot' feed for the amount of exercise he is getting?

Take and Give Exercise: (for the tense but not-nervous horse and tense rider)
This exercise allows for the rider to take pressure off the horse's mouth if they tend to have rock hands or tense arms. Ride on a 20m circle in a balanced SLOW trot. Take your normal contact for a few strides then slide your reins up your horse's neck letting him stretch for another few strides without rising faster and then back to your normal contact. When your horse remains in the same tempo at trot while doing this exercise, increase the amount of strides that you slide your reins up the horse's neck. Once your horse is happy riding with a loose contact, continue to let your arms relax and keep the looser contact. Careful you don't lean forward. Return to the normal contacct focussing attention on keeping your arms soft but not floppy. If you feel your arms get tense or your horse strain against the bit, slide your hands up your horse's neck again. It might take a week or so to get used to soft arms, but it's definetley worth when you have a relaxed horse. The same applies for canter. It doesn't matter about if your horse is on the bit for this. Let your horse have his head in his usual head carriage position. Later with more work, you can ride your horse from behind to bring him down.
At canter, let your reins go loose. Put your arms forward for a couple/few strides then bring them back to the looser contact. Make sure you sit deep in the saddle and don't get thrown forward. Keep your hips moving slowly (fast hips will make the horse go faster). Squeeze your thighs into the saddle and make sure you are sitting on your coccyx and not on your pubic bone.
 

Once you've done the above exercise and your horse is still not relaxed, try some of the following
The Spiral: (for the tense/ nervous or stiff horse)
Attempt this at walk first. Make sure you have correct bend to the inside. Keep your inside leg on the girth (to keep you horse from falling into the circle) and keep your outside leg behind the girth (to keep your horse from straying out of the circle). Give and take your inside rein to reinforce bend and flexion. Keep your outside rein soft.
Start on a 20m circle. Without great angle, slowly apply your outside leg and enforce inside bend. In a leg-yielding movement bring your horse on a gentle angle smaller into the circle, and continue until you are almost doing a turn on the forehand.
Starting from the outside and winding down so
small until it becomes almost a turn on the forehand.

Once you've reached the middle, begin to spiral out in the same manner but this time using your inside leg but continue to maintain the inside bend. You will be leg-yielding to the outside track. Watch that your horse is not only bending his neck but bending through the body.
Once you have established this nicely at walk and your horse is quite supple, begin this at trot. To get your horse's hind quarters working, once you have spiralled in from the outside, stay on the small circle and push your horse hard keeping both your inside and outside legs squeezing. This will be difficult for your horse but he will begin to use his hindquarters. This is also possible to do at canter but ofcourse unless you are able to do a canter pirouette you will not be able to go as small as in the walk and trot. *remember. Cantering on a very small circle should only be done when your horse's balance at walk trot and canter is fully established.

The 10m (or smaller) Figure of Eight: (for the stiff and nervous/tense horse)
This is just a simple exercise for enabling bend and calming down a fast horse. It also helps the horse concentrate on leg aids and use his hind quarters.
For a 10m figure of eight, ride inbetween (for example) F and K (on a standard sized dressage arena). Ride a semi circle to the right from F so it ends on the centre-line. When you hit the centre line, halt, change flexion and continue to the left on a semi circle to hit K but this time continue on another semi circle to hit the centre line again. Only to begin with I recomend to halt and change flexion as sometimes it is difficult (for the novice rider and horse) to change flexion through walk. You can do this through trot and canter also (but in canter remembering to change lead unless you and your horse is capable of doing fly changes!) The crossing over the centre-line is a good place to pratice transitions through trot-walk-trot, trot-halt-trot, canter-trot-canter, canter-walk-canter or even canter-halt-canter.
The sizes of the circles can vary depending on your horse's balance and suppleness. Aim to get your horse bending properly and suppley on a ten metre circle, then make it smaller until you begin to work your horse suppley on a very small figure of eight.

The basic figure of eight: