The pike push-up and the regular push-up are two different upper body exercises that target different muscle groups and require different body positions and techniques. Here’s how they differ:

Pike Push-Up

1. Primary Muscles Worked: Shoulders (deltoids), upper chest, and triceps.
2. Position: Start in a pike position, with your hips high and your body forming an inverted V-shape. Your feet and hands should be on the ground, and your head should be pointed downwards towards the ground.
3. Movement: Bend your elbows to lower your head towards the ground, focusing the effort on your shoulders and upper chest. Push back up to the starting position.
4. Difficulty: Generally more challenging as it puts a greater emphasis on the shoulder muscles and requires more shoulder stability and strength.
5. Modifications: You can increase the difficulty by elevating your feet or changing the hand positioning to focus on different muscle groups.

Regular Push-Up

1. Primary Muscles Worked: Chest (pectoral muscles), shoulders (deltoids), and triceps.
2. Position: Start in a plank position, with your hands shoulder-width apart and your body forming a straight line from head to heels.
3. Movement: Bend your elbows to lower your body towards the ground, keeping your body in a straight line. Push back up to the starting position, focusing the effort on your chest and triceps.
4. Difficulty: Generally more accessible for beginners compared to pike push-ups. It is easier to maintain proper form and technique.
5. Modifications: You can modify the exercise to make it easier (by doing them on your knees) or more challenging (by elevating your feet or adding weight).

In summary, the pike push-up is more shoulder-focused and resembles an overhead press movement, while the regular push-up targets the chest muscles more effectively, resembling a bench press movement.

The exact difference in how much the deltoids are worked between a regular push-up and a pike push-up can be somewhat subjective and dependent on individual biomechanics, but we can discuss the general differences:

In a regular push-up, the deltoids (specifically the anterior deltoids) are indeed engaged, as they assist in the pressing motion. However, the primary muscles being worked are the pectoral muscles (chest). The deltoids are working, but they are not the primary focus.

In contrast, a pike push-up places a greater emphasis on the deltoids. In this exercise, you’re essentially doing a vertical push (similar to a shoulder press), which targets the deltoids to a greater degree, especially the anterior and medial deltoids. The higher pike position shifts more of your body weight onto the shoulders, requiring them to work harder compared to a regular push-up.

If we were to quantify the difference, we might say that a pike push-up works the deltoids significantly more, possibly to a degree of 50-75% more engagement, compared to regular push-ups. However, it is essential to note that this is a very rough estimate and can vary between individuals and depending on exact form and technique. It would be best to rely on personal experience and possibly muscle activation studies for more precise data.