diff --git a/StravaCompetitor/requirements.txt b/StravaCompetitor/requirements.txt
new file mode 100644
index 0000000..8b9b52c
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+++ b/StravaCompetitor/requirements.txt
@@ -0,0 +1,2 @@
+haversine==2.8.0
+typing-extensions==4.8.0
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diff --git a/StravaCompetitor/utils.py b/StravaCompetitor/utils.py
new file mode 100644
index 0000000..ff230e9
--- /dev/null
+++ b/StravaCompetitor/utils.py
@@ -0,0 +1,183 @@
+import haversine
+import datetime
+import json
+import os
+from typing import Dict, List, Tuple, Optional, Union, Any
+
+def calculate_distance(coords: List[Tuple[float, float]]) -> float:
+    """
+    Calculate total distance in kilometers given a list of GPS coordinates.
+    
+    Args:
+        coords: List of (latitude, longitude) tuples
+        
+    Returns:
+        Total distance in kilometers
+    """
+    total_distance = 0.0
+    
+    for i in range(len(coords) - 1):
+        # Calculate distance between consecutive points using haversine formula
+        distance = haversine.haversine(coords[i], coords[i+1], unit='km')
+        total_distance += distance
+        
+    return total_distance
+
+def calculate_elevation_gain(elevation_data: List[float]) -> float:
+    """
+    Calculate total elevation gain in meters from a list of elevation points.
+    
+    Args:
+        elevation_data: List of elevation values in meters
+        
+    Returns:
+        Total elevation gain in meters
+    """
+    gain = 0.0
+    
+    for i in range(len(elevation_data) - 1):
+        # Only count positive elevation changes
+        diff = elevation_data[i+1] - elevation_data[i]
+        if diff > 0:
+            gain += diff
+            
+    return gain
+
+def calculate_pace(distance_km: float, duration_seconds: int) -> Tuple[int, int]:
+    """
+    Calculate pace in minutes per kilometer.
+    
+    Args:
+        distance_km: Distance in kilometers
+        duration_seconds: Duration in seconds
+        
+    Returns:
+        Tuple of (minutes, seconds) per kilometer
+    """
+    if distance_km <= 0:
+        return (0, 0)
+    
+    # Calculate seconds per kilometer
+    seconds_per_km = duration_seconds / distance_km
+    
+    # Convert to minutes and seconds
+    minutes = int(seconds_per_km // 60)
+    seconds = int(seconds_per_km % 60)
+    
+    return (minutes, seconds)
+
+def save_activity(user_id: str, activity_data: Dict[str, Any], 
+                  base_dir: str = "data/activities") -> str:
+    """
+    Save activity data to disk and return the activity ID.
+    
+    Args:
+        user_id: Unique identifier for the user
+        activity_data: Dictionary containing activity information
+        base_dir: Base directory for storing activity data
+        
+    Returns:
+        Activity ID
+    """
+    # Generate a unique activity ID
+    activity_id = f"{user_id}_{datetime.datetime.now().strftime('%Y%m%d%H%M%S')}"
+    
+    # Add activity ID and timestamp to the data
+    activity_data["id"] = activity_id
+    activity_data["timestamp"] = datetime.datetime.now().isoformat()
+    
+    # Create user directory if it doesn't exist
+    user_dir = os.path.join(base_dir, user_id)
+    os.makedirs(user_dir, exist_ok=True)
+    
+    # Save activity data as JSON
+    file_path = os.path.join(user_dir, f"{activity_id}.json")
+    with open(file_path, "w") as f:
+        json.dump(activity_data, f, indent=2)
+    
+    return activity_id
+
+def get_user_activities(user_id: str, limit: Optional[int] = None,
+                        activity_type: Optional[str] = None,
+                        base_dir: str = "data/activities") -> List[Dict[str, Any]]:
+    """
+    Retrieve a user's activities with optional filtering.
+    
+    Args:
+        user_id: Unique identifier for the user
+        limit: Maximum number of activities to return (newest first)
+        activity_type: Filter by activity type (e.g., "run", "ride", "swim")
+        base_dir: Base directory for storing activity data
+        
+    Returns:
+        List of activity data dictionaries
+    """
+    user_dir = os.path.join(base_dir, user_id)
+    
+    # Return empty list if user directory doesn't exist
+    if not os.path.exists(user_dir):
+        return []
+    
+    activities = []
+    
+    # Get all JSON files in the user directory
+    for filename in os.listdir(user_dir):
+        if filename.endswith(".json"):
+            file_path = os.path.join(user_dir, filename)
+            with open(file_path, "r") as f:
+                activity = json.load(f)
+                
+                # Apply activity type filter if provided
+                if activity_type is None or activity.get("type") == activity_type:
+                    activities.append(activity)
+    
+    # Sort activities by timestamp (newest first)
+    activities.sort(key=lambda x: x.get("timestamp", ""), reverse=True)
+    
+    # Apply limit if provided
+    if limit is not None and limit > 0:
+        activities = activities[:limit]
+    
+    return activities
+
+def calculate_statistics(activities: List[Dict[str, Any]]) -> Dict[str, Any]:
+    """
+    Calculate summary statistics for a list of activities.
+    
+    Args:
+        activities: List of activity dictionaries
+        
+    Returns:
+        Dictionary with summary statistics
+    """
+    if not activities:
+        return {
+            "total_activities": 0,
+            "total_distance": 0,
+            "total_elevation_gain": 0,
+            "total_duration": 0,
+            "activity_types": {}
+        }
+    
+    stats = {
+        "total_activities": len(activities),
+        "total_distance": 0,
+        "total_elevation_gain": 0,
+        "total_duration": 0,
+        "activity_types": {}
+    }
+    
+    for activity in activities:
+        # Accumulate totals
+        stats["total_distance"] += activity.get("distance", 0)
+        stats["total_elevation_gain"] += activity.get("elevation_gain", 0)
+        stats["total_duration"] += activity.get("duration", 0)
+        
+        # Count by activity type
+        activity_type = activity.get("type", "unknown")
+        if activity_type in stats["activity_types"]:
+            stats["activity_types"][activity_type] += 1
+        else:
+            stats["activity_types"][activity_type] = 1
+    
+    return stats
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