BASIC BIOMECHANICS
8th Edition
ISBN: 9781259913877
Author: Hall
Publisher: RENT MCG
expand_more
expand_more
format_list_bulleted
Concept explainers
Videos
Textbook Question
Chapter 4, Problem 9IP
In Problem 8, how much total stress is present on the fifth lumbar vertebra if the individual holds a 222 N weight bar balanced across his shoulders? (Answer: 29.3 N/cm2)
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
Explain the answer biomechanically
2. a) Label the system provided below, including the reference frame, moment arms and vector forces
with the information provided.
Internal moment arm = 4cm +0.04m
External moment arm relative
to the segment weight = 25cm 0.25m
External moment arm relative
to the load weight = 45cm 40.45m
Segment weight = 50 N
Load weight = 100 N
Lower leg segment angle relative
to horizontal plane = 45°
Quadriceps tendon angle = 45°
Axis of
rotation
MF
SW
LW
2b) Using the figure in 2a., calculate the external torque of the system relative to the normal
component of segment and load weights listed above.
2c) Calculate the amount of both the tangential component of the muscle force and the muscle force
itself required to keep this system in a state of static equilibrium.
With the shoulder flexed at 30°, the moment arm of the deltoid muscle is 2.0 cm. Solve
for the force exerted by the deltoid muscle at the glenohumeral joint give the following
assumptions:
The deltoid is the only active muscle at the glenohumeral joint
The weight of the humerus is 48 N.
The center of gravity of the humerus is located 30 cm from the shoulder center of
rotation
STATIC EQUILIBRIUM EQUATIONS
CONSIDERING ONLY THE DELTOID MUSCLE
Fo
MA =
18 Cn
COR
B=55".
0-30°
RaF 30 cm
FG = 24 N
Chapter 4 Solutions
BASIC BIOMECHANICS
Ch. 4 - Prob. 1IPCh. 4 - Prob. 2IPCh. 4 - Prob. 3IPCh. 4 - Prob. 4IPCh. 4 - Prob. 5IPCh. 4 - Prob. 6IPCh. 4 - What kinds of fractures are produced only by...Ch. 4 - Prob. 8IPCh. 4 - In Problem 8, how much total stress is present on...Ch. 4 - Why are men less prone than women to vertebral...
Ch. 4 - Hypothesize about the way or ways in which each of...Ch. 4 - Prob. 2APCh. 4 - Prob. 3APCh. 4 - Hypothesize as to the ability of bone to resist...Ch. 4 - How are the bones of birds and fish adapted for...Ch. 4 - Prob. 6APCh. 4 - Hypothesize as to why men are less prone to...Ch. 4 - Prob. 8APCh. 4 - How much compression is exerted on the radius at...Ch. 4 - If the anterior and posterior deltoids both insert...
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, bioengineering and related others by exploring similar questions and additional content below.Similar questions
- The adjacent diagram displays the joint reaction force between the acetabulum and femoral head for the right leg during single leg stance. Also shown are the abductor muscle force (AMF), the weight of the body above the level of the stance hip (W) and their corresponding moment arms with respect to the joint centre (D and D1). If the right leg weighs 1/6 of total body weight, the ratio of D1 to D is 2.4, and AMF is angled at 30 degrees relative to the vertical, calculate the: Abductor muscle force (2 marks). Hip joint reaction force (2 marks). Express both answers as multiples of total body weightarrow_forwardIf an individual does training with only the right knee extensor muscles, it is common to see increase in strength in knee extension force for the right leg and an increase in strength in the knee extension force of the left leg (although the increase in force is typically not to the same extent as the force increase in the right leg) a.) True b.) Falsearrow_forward< The three main forces that act on the patella are shown on the diagram of the knee joint below. These forces are the quadriceps muscle force (FQ), the patella ligament force (FPL), and the patellofemoral joint reaction force (FPF). The angles a and ẞ are with respect to a line that is perpendicular to FPF. Assuming a = 15°, ẞ = 20°, and FQ = 3725 N, use equations for static equilibrium to calculate (a) FPL, and (b) FPF. (Hint: To solve this problem consider using a coordinate system that is aligned with the principal axes of the patella instead of the usual vertical and horizontal axes). (c) Many people assume FQ and FPL are always equal in magnitude but this is only true under certain circumstances. Under what conditions are FQ and FPL equal in magnitude? Fo FPF FP B GriffithUNIVERSITY Queensland Australiaarrow_forward
- Is there a difference in the time to fatigue of the dominant and non-dominant arm? Cite relevant experimental data.arrow_forwardAs an athletic trainer, you are supervising the rehabilitation of a junior baseball pitcher who underwent minor shoulder surgery during the winter. His rehabilitation is progressing well and is now able to do all the exercises you prescribe. You are considering adding some functional exercises to his program. Fully explain what is meant by functional exercises and then be creative and suggest five functional exercises to stress his shoulder. Then explain why each exercise would be considered a functional exercise.arrow_forwarda) Between EMG activity and force output, which changes with grip spacing and which stays constant? b) Which one of the principles below explains the relationship between grip spacing and force output? -Force-velocity (load-velocity) -Length-tension -Frequency-tension c) Explain the difference in sarcomere overlap as spacer width increases.arrow_forward
- A) Describe the difference between strength and power during a squat. Provide a quantitative example that illustrates the difference. B) During a squat, the weight you have on your shoulders has a certain amount of gravitational potential energy. As you squat down and come to a stop at the bottom of the squat, some of that energy is lost. Where does it go?arrow_forwardHow much force must be produced by the biceps brachii, attaching at 90? to the radius at 3 cm from the center of rotation at the elbow joint, to support a weight of 200 N held in the hand at a distance of 30 cm from the elbow joint? (Neglect the weight of the forearm and hand, and neglect any action of other muscles)arrow_forward30³ V F2 ● 3 E CALF RAISES 80 F3 Bones Muscles Joint type(s) Movement(s) Name an activity you could do in daily life that uses the same movement as calf raises: MEDICINE BALL OVER/UNDER Bones Muscles Joint type(s) Movement(s) Name an activity you could do in daily life that uses the same movement as over and under: STRETCH BAND LATERAL RAISES 6,884 Bones Muscles Joint type(s) Movement(s) Name an activity you could do in daily life that uses the same movement as lateral raise: DUMBBELL FRONT SQUAT DEC 6 $ 4 a D F4 A % 5 G F5 W 0 F6 MacBook Air * 6 188880BA 7 F7 3 F8 P ( 9 F9arrow_forward
- Before testing a true 1-RM exercise, why should you allow your client to complete 3 trial repetitions first? Select 2 correct answer(s) To reduce risk of injury To ensure form is correct To fatigue the muscles to a "normal" functional strength To focus on the eccentric and concentric portions of the movementarrow_forwardWhich of these increases force production? 1. Increasing the velocity of the concentric contraction 2. Increasing the velocity of the eccentric contraction 3. Increasing strength of neural stimulation 4. Holding your breath during contraction 5. Increasing frequency of neural stimulation 6. Decreasing the velocity of the concentric contraction 7. Starting the contraction with the joint in full extension 8. Decreasing the velocity of the eccentric contractionarrow_forwardThese figures show that: S Vor (1-min¹) 30 A 2.5 20 1.5 1.0 0.5 (50) 10 Concentric Eccentric Exercise rate (100) 20 (150) Integrated EMG (counts min) B 600 400 200 (50) 30 10 Mean torque on pedals (Nm) (100) Concentric 20 Exercise rate (200) (150) Eccentric 30 O concentric contractions require more oxygen and more EMG than eccentric contractions O concentric contractions are easier to perform than eccentric contractions O eccentric contractions place a greater demand on the cardiovascular and nervous systems compared to concentric contractions O eccentric contractions use less oxygen but more EMG than concentric contractionsarrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
Basic BiomechanicsBioengineeringISBN:9780073522760Author:Susan J HallPublisher:McGraw-Hill Education
Basic Biomechanics
Bioengineering
ISBN:9780073522760
Author:Susan J Hall
Publisher:McGraw-Hill Education
GCSE PE - ANTAGONISTIC MUSCLE ACTION - Anatomy and Physiology (Skeletal and Muscular System - 1.5); Author: igpe_complete;https://www.youtube.com/watch?v=6hm_9jQRoO4;License: Standard Youtube License