This weekend, two of the season's biggest fitness events are going head to head on opposite sides of the city.

In one corner, San Francisco's homegrown City Fit Fest will make its debut at Crissy Field. In the other, the Los Angeles–based fitness empire Tone It Up will take over Civic Center Plaza for the SF stop along its national tour.

While you could carb up on Friday night and try jetting back and forth on Saturday to lunge with K+K (as the Tone It Up community refers to founders Karena Dawn and Katrina Scott) at Civic Center, and to then Sweat and Flow with Shauna Harrison in the Marina, and back then to Civic Center for push-ups and HIIT with Jillian Michaels. But if you are trying to fit anything else into your day, like a meal or any non-workout activities, you may need to choose. Here's what's happening at each event.

Tone It Up Tour

On their inaugural cross-country tour, K+K and celeb trainer Jillian Michaels are leading nearly two hours of high intensity interval training (HIIT)–based workouts with a dash of yoga.

The Civic Center event begins at 3pm with a 30-minute Core Power yoga session. Michaels will lead a second 30-minute workout, and to wrap up, K+K will lead a 45-minute session in the style of their famous Booty Call. Afterward, VIP ticket holders can meet and greet with the TIU crew (6-8pm) in the Rosé Garden for glasses of post-workout wine, DJ beats, gift bags, and free massages courtesy of Zeel.

// Noon to 5pm, Saturday, Sept. 16 at Civic Center Plaza; tickets ($110 or $220-260 for VIP) are available at ticketweb.com; toneitup.com.

City Fit Fest

Founded by super fit Bay Area locals Nate Mezmer and Anthony Black, Fit Fest's inaugural event will appeal to yogis and includes a lineup of national and local fitness bosses leading classes throughout Crissy Field.

Get the morning going with a 50-minute, DJ-accompanied Vinyasa session led by The Pad's Nicole Cronin (10:30am); be fierce in Janet Stone's Beyoncé-inspired yoga class (a Wanderlust favorite); and look for guest appearances by Kerri Verna of @BeachYogaGirl fame and Kaisa Keranen (aka @KaisaFit), both teaching in the afternoon. There will also be short sessions on strength and mobility taught throughout the day. Mindfulness workshops will include a journaling session with Julie Aiello of Outdoor Yoga and a panel discussion on the mindful hustle for healthy entrepreneurs. Plus, music and games!

// 10am to 7pm, Saturday, Sept. 16 at Crissy Field; tickets ($80), are available at Eventbrite.