PREDICTING CALORIC EXPENDITURE

ONE ARM DUMBBELL ROW
[An innovative analysis] – A little aspect of Physio-analysis

Imagine an individual who weighs about 70 kg. The features of his upper limb [55 cm long] are as follows;

Arm length [Shoulder to elbow distance] = 25 cm
Forearm length [Elbow to wrist distance] = 30 cm

This individual now attempts to perform an exercise called ‘One arm dumbbell row’ with 8 kg dumbbell. When he completely performs one row from neutral position [figure:1], his arm remains elevated to about 30 degrees from horizontal [figure:2].

[ Figure:1] [ Figure:2]



Calculation [This type of formulae, I am planning to innovate and introduce in my textbook on Biomechanics, having Pythagorean theorem as basis]

The Total Distance Traveled by Dumbbell [TDTD] from neutral position to its position as in figure:2 can be calculated as follows;

TDTD = √[Upper limb length – (Forearm length – {Arm length x sine 30 degrees})]2 - [Arm length x cosine 30 degrees]2

= √ [ 55 cm – (30 cm – {25 cm x 0.5})]2 - [25 cm x 0.866]2

= √ 1406 cm2 – 467 cm2

= √939 cm2

Therefore, TDTD = 31 cm [approx] or 0.31 meters.

This TDTD can be simply considered as ‘D’ of the formula of WORK DONE. [Note: TDTD measurement can also be replaced with a simple inch tape measure of distance traveled by Dumbbell]


WORK DONE [W] = Force [F] x Distance traveled [D]

When the work done [W] is computed in joules, it is possible to correlate joules with calories. Hence , we can guesstimate the calories burnt by an individual during the training session by summating the joule expenditure of all types of his workouts.

PREVALENCE OF RESTRICTED INTERNAL ROTATION OF LEFT HIP JOINT

Background: This study was not intentionally directed to identify the prevalence of restricted internal rotation of left hip joint. While conducting general musculo-skeletal and cardio-respiratory screenings for various individuals at Maverick Fitness Studio, Bangalore, India, the prevalence of restricted internal rotation of left hip joint was noticed. Thereafter, a simple statistical report was developed to publicize this unusual finding.

Method: The individual undergoing screening has to be in prone position. The Physiotherapist passively bends both the legs of that individual at knees up to 90º. Then ensuring the pelvic stability, he applies mild force to move the vertically placed legs away from each other to create internal rotation mechanism in hip joints, while the thighs remain parallel to themselves. Observing the deviations of legs from standing behind, the Physiotherapist compares the range of motion taking place at hips (non-goniometric method).

Findings: About 160 males and 88 females were examined. It was found that 76.2 % males and 66 % females have restricted internal rotation of left hip joint. Among these males and females, only few were foreigners but most of them were Indians. Persons who did not have restricted internal rotation of left hip joint either had [a] equal adequate range or inadequate range of internal rotation of hips [b] restricted internal of right hip joint . However, the accurate differences between the ranges of motion of internal rotation of hips were not measured using goniometer.

Interpretation: Normally, internal rotation of hip joints can get limited by piriformis muscle (including other soft tissues also that has orientation and attachments resembling pirifromis). Piriformis is a muscle in the gluteal region that can produce external rotation of hip joint. So, the restricted internal rotation of left hip joint in various individuals may be due to left piriformis tightness.

Conclusion: Although plenty of reasons might exist for highly prevalent restricted internal rotation of left hip joint, at this stage only one plausible hypothesis can be used to correlate this huge number of cases of 'Restricted Internal Rotation of Left Hip Joint'. Preferential acceptance of body weight on the right lower extremity [relaxed stance] can be that plausible reason. Relaxed stance on the right lower extremity with sufficient external rotation of left lower extremity [left piriformis has to shorten to promote greater acceptance of weight on the right lower extremity] can lead to shortening of left piriformis muscle leading to restricted internal rotation of left hip joint. Especially, tightness of piriformis has been emphasized and considered as one of the important causes of sciatica {PIRIFORMIS SYNDROME}. So, more number of individuals may be prevalently developing SCIATICA on the left side {radiating pain along the back of thigh and leg}, if the tightness of left piriformis muscle remains undetected or neglected-despite-detection. A detailed study on the prevalence of left sciatica caused by the tightness of left piriformis muscle would enable further digging out of the facts to protect people from this excruciating disorder.