Strength & Flexibility: There's More to it Than That


In both the healthcare and fitness industries there is an obvious emphasis on improving strength and flexibility. Whether you have low back pain due to “inflexible” hips or you have a poor vertical jump due to “weak” hips, strength and flexibility are the focus of many rehabilitation and training programs today. But, is there more to it than that? In other words, does stretching and strengthening address the underlining cause of measured inflexibility and weakness? This short article will give an overview on the components of strength and flexibility, and how we can address those components to improve outcomes in our clients.

What is strength?

Strength is usually defined as the ability of a muscle to generate force to produce or prevent a motion at one joint, or across multiple joints. How is strength traditionally tested? Strength is usually measured with manual muscle testing, hand-help dynamometry or 1- repetition max testing. All of these tests consist of aligning the body into a position to bias one or multiple muscles, followed by the client giving 100% effort to either produce or prevent a motion or movement.

How is strength traditionally trained?

To improve strength, the American College of Sports Medicine‘s (ASCM) guidelines suggest performing 2-3 sets of 8-12 repetitions of 80% of an individuals 1 repetition maximum 2-3 non-consecutive days a week. This sounds great, as long as the underlying factor at question is… strength.

Factors that influence strength:

• Gender: males tend to have more strength than females due to hormonal differences

• Age: strength is typically less in pre-pubertal and geriatric individuals

• Muscle mass: usually (but not always) strength is positively correlated with the cross-sectional area of a muscle

• Biomechanical alignment: strength can decrease if a muscle is placed in an excessively shortened or lengthened position

• Pain: pain due to swelling in a joint has been known to inhibit muscles that cross that joint

• Physiology: lower levels of hydration, electrolytes, creatine, etc. can all decrease muscle function

• Motor control: the ability to control movement, as planned in the motor control center of the brain and performed by the musculoskeletal system

What is flexibility?

Flexibility is defined as an ability of a muscle to lengthen across one joint or multiple joints.

How is flexibility traditionally tested?

Flexibility can be tested by measuring a joint’s range of motion while assessing the “end-feel” to determine if the restriction is muscle or joint-related. Flexibility can also be assessed across multiple joints by observing functional movements such as bending forward.

How is flexibility traditionally trained?

Traditionally flexibility is addressed by either static or dynamic stretching. Research shows that stretching a muscle at end-range for 30-60 seconds can increase the short-term resting length of that muscle.

Factors that Influence Flexibility:

• Gender: females tend to be more flexible than males due to hormonal differences

• Age: pre-adolescents and young adults tend to be more flexible than teenagers and older adults

• Physiology: muscles can lose their elasticity due to dehydration

• Pain: pain may limit a muscles ability to lengthen, especially if the muscle is damaged

• Biomechanical alignment: a muscle can either be excessively lengthened or shortened in a resting position due to poor or asymmetrical posture

• Motor control: during a movement, if a muscle is contracting when it is suppose to be relaxing, then that muscle will not be able to lengthen if needed Prerequisites for Training:

Creating an Environment that Promotes Functional Strength and Flexibility

• Gender: sorry cant help with this one

• Age: unless you are in Never-Never Land, my advice is to age yourself

• Physiology: diet and lifestyle choices can affect your body’s form and function. Staying hydrated and eating whole foods that are not processed should give the body what it needs to function.

• Pain: if pain is present during training, then compensation may be occurring in order to not compromise the area of pain during movement

• Biomechanical alignment: measuring whether a person is neutrally aligned or not, will determine whether muscles are over-lengthened or –shortened

• Motor control: if any of the aforementioned factors are present, then motor control is likely being altered. For example: if a hamstring is over-lengthened due to a pelvis that is rotated forward, then during standing the hip flexors, quadriceps, calves and low back muscles are likely being used excessively in order to stabilize the pelvis.

So what does all this mean?

Simply put, without addressing the components of strength and flexibility before training, we are promoting compensation and increasing the risk for injury and pathology. Strengthening a dysfunctional movement pattern only reinforces the dysfunction and stretching a muscle that is currently lengthened can contribute to pathological laxity. The Postural Restoration Institute recognizes and identifies individuals who are pathologically lax; in other words, people who have over-stretched soft tissue structures without addressing postural neutrality first. These hypermobile individuals may have unstable joints, which result in the body reflexively toning/tightening up certain muscles as compensation for that instability. This is a normal survival mechanism.

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