4.6: Why Muscle Matters

National Health Education Standards (NHES)

• Compare and contrast the good things about (and the challenges of) practicing healthy habits, like being active every day.
• Set goals to improve your health, such as being more physically active.

Wellness Guidelines

• Be physically active more often.
• Spend less time sitting still.

Instructions: Work in a group, with a partner, or think about these questions on your own. If someone has made progress toward their goal, celebrate it! If someone wants to change their goal, they can get one-on-one help.

Discuss: Let's talk about our SMART Goals (goals that are Specific, Measurable, Achievable, Relevant, and Time-based).

• How is your current SMART goal going?
• What are some ways you could do better at reaching your goal? (These are called "Grows.")
• What are some ways you're already doing well? (These are called "Glows.")

GUIDELINE: Be more physically active more often, and spend less time sitting.

Discuss: Which guideline do you think matches today's lesson? Who has a SMART Goal connected to this guideline?

Instructions: Pick one activity to do:

1. Guideline Popcorn: As a group, quickly call out all 8 guidelines, one person after another.
2. Guideline Charades: Split into groups. Each group gets a guideline and has to act it out silently while everyone else guesses.
3. Two Truths and One Lie:
4. Truth 1: If you don't use your muscles, you'll lose them as you get older.
5. Truth 2: Building muscle helps make your bones stronger.
6. Lie: Only athletes need to exercise and build muscle.
7. Questions to discuss or write about:
8. What are your favorite exercises?
9. Which muscles do those exercises work?
10. Which exercises do you think count as "muscle-strengthening"?
11. How often do you do muscle-strengthening exercises?

This lesson will cover why it's important to build muscle, strength, and endurance (the ability to keep going without getting tired). You'll use worksheets and a slides presentation, plus these materials: a whiteboard eraser (or something similar), and simple tools for exercises, like a water bottle and a textbook.

Today's activities:

• Do Now
• The Magic of Muscles
• Endurance and Strength
• No Weights, No Problem Circuits
• Exit Ticket

Key Vocabulary

(Based on definitions from HHS, 2008; CDC, 2004; Dor-Haim et al., 2018)

• Exercise: Body movement that uses energy and is planned, structured, repeated, and done on purpose.
• Fitness: Being able to do your daily activities with energy, without getting tired.
• Insulin: A hormone made by the pancreas that helps sugar (glucose) from food move into your cells so your body can use it for energy.
• Body Composition: A way of measuring different parts of the body, like total weight, fat, muscle, and bone.
• Muscle-strengthening: Exercises that make your muscles work harder than usual by pushing or pulling against weight or force.
• Bone-strengthening: Exercises that put impact or pulling force on your bones.
• Muscular Strength: How much force you can apply, or how much weight you can lift.
• Muscular Endurance: How many times, or how long, you can keep applying force before getting tired.
• Circuit Training: A workout that mixes strength exercises with cardio (aerobic) exercises, one right after another.
• Repetition: The number of times you lift a weight (or do a move) in a row.

Do Now

Set Up: Show the image described below on a board or projector.

Instructions:

• First, define exercise: movement of the body that uses energy and is planned, structured, repeated, and done on purpose (HHS, 2008).
• As a group, look at an image of a person's body and find each muscle group listed below. Then figure out an exercise that would strengthen it:

1. Trapezius: Around the neck — strengthened with shrugs.
2. Deltoids: Top of the arm — strengthened with shoulder presses.
3. Pectoralis Major: The chest — strengthened with bench presses.
4. Latissimus Dorsi: The back — strengthened with lat pulldowns.
5. Biceps: Front of the arm — strengthened with curls.
6. Triceps: Back of the arm — strengthened with pulldowns.
7. Abdominals: Front, sides, and back of your torso (middle body) — strengthened with crunches.
8. Quadriceps: Front of the thigh — strengthened with squats.
9. Hamstrings: Back of the upper leg — strengthened with lunges.
10. Gastrocnemius (calves): Back of the lower leg — strengthened with calf raises.
11. Gluteus Maximus: Your rear end — strengthened with leg presses.

Discuss: Now that you know some of the major muscles in your body, let's learn more about the muscular system and how it connects to your overall fitness. Remember, fitness means being able to do your daily tasks with energy, without getting tired (HHS, 2008).

Good to Know: The Magic of Muscles

Did you know the human body has over 600 muscles? That makes sense when you think about how much we depend on our muscles — from running, to getting out of bed, to pumping blood through our bodies.

Some muscles you control on purpose, but others do their job automatically, without you even thinking about it. Can you think of an example of a muscle that works on its own? The heart is one!

Optional: Watch a video on the muscular system or a video on muscle growth (links available with the original lesson).

Why might building muscle be an important part of your fitness? Here are some possible answers (CDC, 2018):

• It helps you grow stronger and move more efficiently.
• It helps make your bones stronger.
• It lowers your risk of getting injured.
• It improves the health of your heart and lungs.
• It boosts insulin sensitivity (Bird & Hawley, 2017). Remember, insulin is a hormone made by the pancreas that helps sugar from food get into your cells for energy (NIH, 2016). If your body is more sensitive to insulin, it needs less of it to keep your blood sugar at a healthy level.
• It helps you manage your weight and protects against obesity (being very overweight).
• It can reduce feelings of anxiety and depression.

As part of getting 60 minutes of physical activity every day, make sure to include muscle-strengthening or bone-strengthening activities on at least 3 days each week (HHS, 2008).

• Muscle-strengthening activities make your muscles work harder than usual by pushing or pulling against weight or force (HHS, 2008).
• Bone-strengthening activities create impact or pulling force on your bones (HHS, 2008).

Can you think of examples of muscle- and bone-strengthening exercises? Here are some:

Muscle and Bone Strengthening Activities:
Sit-ups or crunches, push-ups, pull-ups, planks, lunges, squats, wall sits, weightlifting, tug of war, rock climbing, monkey bars, resistance bands, hopping, skipping, jumping jacks, sprinting, surfing, and sports like gymnastics, basketball, volleyball, tennis, and football.

Real World Relevance: Strength and Endurance

Muscular strength and muscular endurance are two important qualities you need to build in your muscles.

• Muscular strength is how much force you can apply, or how much weight you can lift.
• Muscular endurance is how many times, or how long, you can apply force before you get too tired.

How does muscular strength help with daily activities? It lets you lift, push, or pull heavy things more easily — like grocery bags, luggage, or backpacks.

How can you build muscular strength? Try activities like:

• Resistance training (using free weights or exercise machines)
• Push-ups
• Pull-ups
• Sit-ups
• Weightlifting

Why is muscular endurance important? When you have strong muscular endurance, you can keep doing physical activities for longer without stopping.

How does muscular endurance help with daily activities? Try activities like:

• Walking, jogging, or running
• Weightlifting
• Wall sits
• Planks
• Squats

Muscular endurance and muscular strength are connected — when one improves, the other usually improves too. In fact, most exercises build both at the same time.

Try this: Have a volunteer erase the board for two minutes (or draw imaginary circles on a wall with their palm if there's no board).

Then discuss:

• Which part of this activity used muscular strength? Holding the eraser and pressing it against the board.
• Which part used muscular endurance? Moving the eraser back and forth for two minutes straight.
• How do strength and endurance work together? You need enough strength to hold the eraser, and enough endurance to keep erasing for two minutes. Without strength, you can't have endurance — and most tasks require both.

Next, try this: Pick two volunteers.

• Have one volunteer do 10 full push-ups with their hands placed wider than their shoulders.
• Have the other volunteer do 10 full push-ups with their hands placed shoulder-width apart.

Optional: Watch a video showing how to do a proper push-up.

Discuss:

• Let's think about which muscles were used during the push-ups. Push-ups work your arm and chest muscles, but they're also great for your core (the muscles in your middle).
• Did you notice that both kinds of push-ups use the same muscles, but create different results?
• The way you place your hands — wider or closer together — changes how hard your muscles have to work.
• When your hands are closer together, your chest muscles and triceps have to work harder. This type of push-up is usually harder to do, and it can put more stress on your elbows.
• When your hands are wider apart, you still use your chest and triceps, but the focus shifts more to the outer chest muscles.
• Why should you do both types of push-ups? Doing both helps keep the muscle growth in your upper body balanced (Kim Y-S, 2016).

Hands-On: No Weights, No Problem Circuits

Now it's time to try circuit training! Remember, circuit training combines a set of resistance exercises with a burst of aerobic exercise right afterward (Dor-Haim et al., 2018).

During a circuit training workout, you do resistance exercises one after another with little or no rest in between. Some resistance exercises that don't need weights include push-ups, lunges, and squats.

Between sets of resistance exercises, you'll do an aerobic exercise — like jumping jacks, speed skaters, or jogging in place with high knees.