V-up

The V-up is an exercise for intermediate and advanced fitness enthusiasts.This movement consisnts of the lifting of the limbs and torso while balancing on a small area of the waist.These muscle groups part in the exercise :

Muscles

Target

Rectus Abdominis

Synergists

Iliopsoas
Tensor Fasciae Latae
Pectineus
Sartorius
Rectus Femoris
Adductor Longus
Adductor Brevis
Obliques

Options

According to the method of execution

• Explosive variation with a fast stop

The execution of the movement is at maximum speed, slowing down and stopping at the peak point.
Developing explosive strength and coordination. You could perform this variation with resistance bands.

• Slow variation

This option is carried out within 5 seconds. The slower the limbs and body are moving, the harder the strain on the abdominal muscles. Aims to increase strength endurance and balance.

• With added weight

Dumbbells or sandbags can be used here.Strength and muscle mass.

According to the technique of execution.

• Performance with straight legs

This is a classic and difficult option to perform. It involves all of the sygergists listed above.

• Performance with legs bent at the knees

This is a modified form of the exercise. Suitable for intermediate fitness enthusiasts who want to gradually strengthen abdominal, lumbar and hip muscles. This variation eliminates the involvement of the long head of the quadriceps (Rectus Femoris).

• Performance with a twisting motion

This movement focuses on the obliques. In diagonal twist (left foot / knee to the right hand and vice versa) obliques are the main target.
Performance with elbow support
This is a variant of the exercise in which the focus falls on the lower right sector of the abdominal muscles (Rectus Abdominis), hip adductor muscles and hip muscles.

Method of execution

Preparation

1. Sit on floor or mat. 
2. Lie supine with hands on floor over head.

Execution

1. Simultaneously raise straight legs and torso. 
2. Reach toward raised feet.Try to hold for a second.
3. Return to starting position. Repeat.

Relevancy

This exercise improves strength and strength endurance, balance and increases muscle mass of the abdominal muscles and rendering pelvic muscles, in other words it is an effective ab exercise, and one could get a good abs workout from it. Improves coordination. The many variations of this movement suggest broad opportunities for participation of the V-ups in a variety of workout routines. The only requirement for all the different possibilities and implementations for this exercise is a heathly spine, because it can easily trigger an old trauma.
(sources:bbteam.com,exrx.net)