Abdominal muscles and core: what they do, how to train

01The short answer

02Five muscles, five roles

Cleveland Clinic describes five main abdominal muscles:

• rectus abdominis, at the front, which holds the organs in place and keeps the body stable during movement;
• pyramidalis, a small muscle found in about 80% of people, which helps maintain pressure inside the abdomen;
• external obliques, the largest of the flat muscles, which let the trunk twist from side to side;
• internal obliques, which work with the external ones to twist and turn;
• transversus abdominis, the deepest, which stabilizes the trunk and maintains pressure inside the abdomen.

03The core, wider than the abs

Mayo Clinic defines the core as the centre of the body: the pelvis, lower back, hips and stomach. Training it helps these muscles work together, which improves balance and stability. It adds that strengthening the core may help back pain get better and lower the risk of falls (if you already have back pain, talk to a physiotherapist first), and that weak core muscles can leave you more prone to poor posture, lower back pain and muscle injuries.

Back muscles covers the other side of the core.

04Two simple exercises

• The bridge. Mayo Clinic suggests it for the core: lying on your back with knees bent and your back neutral, neither arched nor pressed into the floor, tighten your stomach, then raise your hips until they line up with your knees and shoulders; hold for three deep breaths, without tilting your hips. Glutes gives more detail.
• Lower back tilt. In its back routine, Mayo Clinic describes this “lower back flexibility exercise”: lying on your back with knees bent, tighten your belly so your lower back lifts from the floor, hold for 5 seconds and relax; then flatten your back by pulling your belly button toward the floor, hold for 5 seconds and relax. Start with 5 repetitions a day, and build up gradually.

Cleveland Clinic adds two habits: stretch every day, both before activity and after it, and tighten your abs when you cough or sneeze.

05Stronger abs, not a flatter stomach

Strengthening your abs and losing belly fat are two different things. Losing belly fat explains what reduces abdominal fat, based on Obesity Canada's guidelines.

06At noon, in a group

Joanie Roussy's women's classes, at noon on weekdays, get you moving in a group: Strong Nation™ syncs cardio and strength to music, with no equipment; Bootcamp moves you from station to station, with and without equipment; Zumba® gets you dancing. Joanie also offers private, personalized 60-minute training sessions on request. Adult karate, mixed and open from age 14, runs in the evening.

07At noon, from downtown

The bridge and the tilt are done on the floor, with no equipment: easy to fit in at home in the evening, after a day downtown. The REM links Gare Centrale to Île-des-Sœurs station. The dojo is at 550 chemin du Golf, suite 010: the getting to the dojo page works out the route by the mode you choose, and the schedule gives the class days.

Sources

1. Cleveland Clinic, “Abdominal Muscles” (2024) — my.clevelandclinic.org/health/body/21755-abdominal-muscles
2. Mayo Clinic, “Core exercises: Why you should strengthen your core muscles” (2026) — www.amerikanhastanesi.org/mayo-clinic-care-network/mayo-clinic-health-information-library/first-aid/core-exercises-why-you-should-strengthen-your-core-muscles
3. Mayo Clinic, “Back exercises in 15 minutes a day” (2026) — www.mayoclinic.org/healthy-lifestyle/adult-health/in-depth/back-pain/art-20546859

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