Age- and Sex-Related Differences and Their Implications for Resistance Exercise

What is chronological age?

Age in years and months.

What is biological age?

Age determined by skeletal, somatic, or sexual maturity (onset of puberty).

Why is biological age more useful than chronological age?

Because the onset of puberty varies greatly among individuals.

At what age range does puberty typically occur in females?

8-13 years.

At what age range does puberty typically occur in males?

9-15 years.

What is the gold standard for assessing biological age?

Skeletal age assessment via radiograph of the left wrist.

What are field measures for assessing biological age?

Somatic assessments like longitudinal growth curve analysis and predicting age from peak height velocity (PHV).

What is peak height velocity (PHV)?

The age of maximum rate of growth during the pubertal growth spurt.

How often should coaches measure height to detect PHV?

Every 3 months.

What are some issues during PHV?

Higher injury risk, altered center of mass, muscle imbalances, tight MTUs, and increased energy demands.

What are S&C considerations during PHV?

Reinforce movement patterns, target flexibility, correct imbalances, lower volume/intensity, and listen for overuse pain.

What is training age?

The length of time a child has consistently followed a supervised strength and conditioning program.

How does training age influence adaptations?

Higher training age = slower adaptation rates.

What factors must be considered in youth training programs?

Ability, technical skill, and training age.

At what ages does peak muscle mass occur?

Females: 16-20; Males: 18-25.

What hormone increases muscle mass in males during puberty?

Testosterone.

What hormone increases fat deposition in females during puberty?

Estrogen.

Where does most bone formation occur?

Diaphysis and growth cartilage (epiphyseal plate, joint surface, apophyseal insertions).

What happens once the epiphyseal plate becomes ossified?

The long bone stops growing.

What is the main concern during bone growth?

Growth plate injuries from trauma or overuse.

How can injury risk to the growth plate be reduced?

Proper technique, progressive load, and professional supervision.

When do boys typically reach peak strength gains?

1.2 years after PHV and 0.8 years after peak weight velocity.

When do girls typically reach peak strength gains?

After PHV, but with greater variation.

At what age is peak strength attained?

About 20 in untrained women, 20-30 in untrained men.

What does myelination completion mean for training?

Full neural maturity allowing maximal strength expression.

What type of strength gains occur in children?

Neural—not hypertrophic—adaptations.

How much strength gain can children achieve with short-term resistance training?

30-40% in 8-20 weeks.

Why are strength gains in children temporary without continued training?

They return to baseline during detraining.

What neural factors contribute to strength gains in children?

Increased motor unit activation, synchronization, recruitment, and firing frequency.

What are benefits of youth resistance training?

Improved motor skill, reduced body fat, better insulin sensitivity, increased BMD, and fewer injuries.

How can overuse injuries be prevented in youth?

Proper coaching, prep conditioning, and delayed specialization.

What is the main potential risk of youth resistance training?

Epiphyseal plate fracture (rare with proper guidance).

Is 1RM testing safe for children?

Yes, under professional supervision.

What should be emphasized in youth RT programs?

Technique, safety, fun, and education over competition.

What are key programming guidelines for youth RT?

Light loads, gradual 5-10% increases, 1-3 sets of 6-15 reps, 2-3 non-consecutive days/week.

What are important lifestyle factors for youth athletes?

Adequate nutrition, sleep, hydration, and multiple-sport participation.

Before puberty, how do boys and girls compare in body size?

No major differences.

What hormonal changes occur at puberty?

Females ↑ estrogen → fat deposition; Males ↑ testosterone → bone & muscle growth.

Why do men tend to be taller?

Longer growth period and later puberty onset.

How do adult females' body composition and muscle mass compare to males?

More fat, less muscle and bone mass.

On average, how does women's absolute strength compare to men's?

About 2/3 of men's strength.

Are strength differences greater in upper or lower body?

Greater in upper body.

When strength is expressed relative to muscle cross-sectional area, do differences remain?

No, differences disappear—muscle quality is equal.

What explains remaining power output differences?

Differences in RFD and neuromuscular recruitment strategies.

Can women increase strength at the same rate as men?

Yes, or even faster (relatively).

What is the Female Athlete Triad?

Low energy availability, menstrual dysfunction (amenorrhea), and low bone mineral density.

What nutrients are vital to prevent the triad?

Calcium, vitamin D, and protein.

What is recommended for upper-body strength development in women?

Add 1-2 extra upper-body exercises or sets, and use multijoint free-weight lifts.

What sports benefit from upper-body RT emphasis?

Volleyball, softball, basketball, tennis, etc.

Why are women more prone to ACL injuries?

Greater joint laxity, smaller ligaments, poor neuromuscular control, and increased dynamic knee valgus.

What training should be prioritized to prevent ACL injuries?

Strength, plyometrics, agility, balance, and movement mechanics.

What happens to bone and muscle with aging?

Loss of both, increasing fall and fracture risk.

What is osteopenia?

BMD between −1 and −2.5 SD of the young adult mean.

What is osteoporosis?

BMD below −2.5 SD of the young adult mean.

What causes bone loss with age?

Physical inactivity, hormonal, nutritional, and genetic factors.

What is sarcopenia?

Age-related loss of muscle mass and strength.

What changes occur after age 30?

Decreased muscle CSA, density, and increased intramuscular fat.

What are main causes of muscle atrophy in aging?

Inactivity and selective denervation of fibers.

Why does power decline faster than strength?

Power depends on fast-twitch fibers and neural drive.

What factors contribute to increased fall risk in seniors?

Reduced strength, power, reaction time, and balance.

What is preactivation?

Muscle activity before ground contact that increases stiffness.

What is cocontraction?

Simultaneous activation of agonist and antagonist muscles for joint stability.

What compensatory change is seen in seniors?

Increased cocontraction due to decreased balance.

What type of training offsets balance and neuromotor decline?

Low-intensity plyos, balance, proprioception, and flexibility.

Does RT alone reduce fall risk?

No, must combine with balance and flexibility work.

What benefits do older adults gain from progressive RT?

Increased strength, power, BMD, and functional capacity.

What type of training improves power in seniors?

High-velocity RT.

What are program considerations for older adults?

Screen for medical issues (PAR-Q+), adjust volume/intensity, and ensure recovery.

Which equipment type is best early in training?

Machines (safer with balance limits).

Which type provides better stimulus overall?

Free weights and multijoint exercises.

What is a safe progression guideline?

Start low (40-50% 1RM, 1 set of 8-12 reps) → progress to 3 sets at 60-80% 1RM.

What are power training recommendations for seniors?

1-3 sets, 6-10 reps at 40-60% 1RM with high speed.

What warm-up and flexibility routines are advised?

5-10-minute warm-up, static stretching before or after.

What breathing technique should older adults avoid?

The Valsalva maneuver.

How much recovery should be given between sessions?

48-72 hours.