LIVERPOOL, England (AP) — Mounting concerns over the safety of the Grand National have forced organisers to make modifications to the course following a review into the world’s most grueling race after two horses died this year.

However, while there will be changes to fence design, landing areas and course irrigation, the size of the field will remain at 40 horses and Becher’s Brook — the much-feared fence criticised for its severity— will keep the same drop and dimensions.

The changes announced Thursday will come into force for the 2013 race, when safety will again be under scrutiny with 10 horses having died in the past 12 editions in the National — sparking fierce criticism from animal welfare groups.

“Balancing the Grand National’s enduring appeal whilst working to reduce risk in the race is a delicate but important balance to strike,” said John Baker, who runs the Aintree course in Liverpool where the race is staged.

“In recent years, we have made significant investments in safety and believe today’s announcement demonstrates we will continue to do so.”

Organisers have attempted to address the recent problems surrounding the beginning of the race, which is launched when a starting tape is lifted, by moving the start 90 yards forward, away from the noise of the crowd in the grandstands. That will shorten the distance of the race to 4 miles, 3 1/2 furlongs.

There were renewed calls in April for the race to be banned after Synchronised, the favourite, and According to Pete were put down after sustaining injuries in an incident-packed 2012 edition. Only 15 of the 40 runners finished the race, with many horses colliding with those who fell at the famous high fences.

The congested field is the biggest criticism levelled at the National, yet the review said the “course and fences allow enough racing surface to accommodate this number of runners”.

Becher’s Brook, where Synchronised and According to Pete fell, has undergone “further levelling of the wider landing zone”, but the drop of between 5 feet, 2 inches and 5 feet, 8 inches remains.

“These latest changes reinforce the fact that we have never stood still when it comes to safety and welfare,” Baker said. “However, we are fully aware in racing that you cannot remove risk altogether.”

The 2013 race will be contested on April 6.