Certainly! For a mobile app dedicated to a fitness coaching service, you would want a color palette that is energizing, positive, and motivating. Here's a color palette that fits those requirements:

1. **Vibrant Blue** - 
                            
                            #0077CC
                        
   - Represents reliability and trust. Good for call-to-action buttons and headers.

2. **Energetic Orange** - 
                            
                            #FFA500
                        
   - Invokes excitement and enthusiasm. Suitable for highlights and accents.

3. **Sleek Silver** - 
                            
                            #C0C0C0
                        
   - A neutral, modern color that can be used for backgrounds and app interfaces.

4. **Clean White** - 
                            
                            #FFFFFF
                        
   - Symbolizes simplicity and cleanliness. Perfect for clean spaces and text.

5. **Motivational Green** - 
                            
                            #22C55E
                        
   - Inspires growth and health. Ideal for progress indicators and success messages.

6. **Charcoal Gray** - 
                            
                            #36454F
                        
   - A strong, balanced color for text and subtle detailing.

**Palette Description:**
This palette combines the trustworthiness and professionalism of vibrant blue with the energy and enthusiasm of orange, which can boost user motivation. Sleek silver and clean white offer a neutral backdrop that is clean and modern, providing a calming balance to the energetic colors. Motivational green adds a sense of growth and renewal, encouraging users to continue their fitness journey. Charcoal gray grounds the palette, providing a strong base for text and details, ensuring readability and sophistication.