Since British Imperial troops, primarily Canadians and Australians, became renowned for this role, what exactly made them so good for it? I find it hard to believe that simply being from those countries meant they had a better grasp of these tactics.
Was it something to do with the training of these soldiers? After all, they weren't mobilised in the millions like British soldiers, so did this mean they were able to be given more specialised training for this role?
And a follow-up if possible:
Canadians and Australians are the best known, but did shock troops come from anywhere else? Were there British units, or equivalents in the other Entente armies?
Physical and organisation differences are key. British troops tended to be drawn from the urban poor, who had grown up in the unhealthy conditions of the slums, and later employment was often found unhealthy factories, mills and mines. Additionally, British Infantry divisions were re-organised to be 'triangular' with 3 brigades of 3 battalions and 3 artillery regiments. Previously they had been organised as 'square' with 3 brigades of 4 infantry battalions. This drop in manpower was adopted by nearly every nation and was largely offset by the increasing proliferation of firepower at the battalion level downward through the creation and deployment of various types of machine guns, mortars, hand grenades etc.
In contrast Australian and Canadian society lacked wide scale heavy industry or urban slum areas, and consequently their soldiers possessed superior physical health and robustness on the battlefield. In addition, they did not adopt the triangular organisation, but still received a vast improvement of firepower. This differing organisation was not taken into account in the planning of operations, they were consequently given the same length of line British troops would hold/attack. The fact then, that they were able to deploy high quality manpower in greater numbers than their allies or opponents was a considerable component to their success
Other units- the Guards Division and Scottish troops tended to be seen as high quality aggressive infantry due to a combination of a increased pickiness (guards) in their manpower selection, or being drawn from a more martial society (Scots). In other Entente Armies the French rated the Senegalese very highly- probably a combination of healthier recruits and a more martial society.
I always had the the impression that the Gurkhas were known as a fierce fighting force. Were they also used as "Shock Troops".
Read battle of Amiens. Modelled on and driven by sir John monash's order of battle. First used at battle of hamel Australia and Canadians side by side. Black day for German army.