Related Experiment Video
Updated: Jan 31, 2026
12:59
Improving Strength, Power, Muscle Aerobic Capacity, and Glucose Tolerance through Short-term Progressive Strength Training Among Elderly People
Published on: July 5, 2017
13.2K
Changes in Dynamic Strength Index in Response to Strength Training.
Paul Comfort1, Christopher Thomas2, Thomas Dos'Santos3
1Directorate of Sport, Exercise and Physiotherapy, University of Salford, Salford, Greater Manchester M6 6PU, UK. p.comfort@salford.ac.uk.
Sports (Basel, Switzerland)
|December 22, 2018
Summary
In-season strength training led to a decrease in the dynamic strength index (DSI) for collegiate athletes. This change was primarily driven by increased force in isometric mid-thigh pulls, not countermovement jumps.
Area of Science:
- Sports Science
- Biomechanics
- Strength and Conditioning
Background:
- The dynamic strength index (DSI) is a key metric for assessing athletic performance and injury risk.
- Understanding how in-season training affects DSI is crucial for optimizing athlete development and preventing overtraining.
Purpose of the Study:
- To investigate the impact of a four-week in-season strength training program on the DSI of collegiate athletes.
- To analyze differential changes in DSI based on initial DSI levels (high vs. low).
Main Methods:
- Twenty-four collegiate athletes participated in a four-week in-season strength training intervention.
- Dynamic strength index (DSI) was calculated pre- and post-training using isometric mid-thigh pulls and countermovement jumps.
- Statistical analyses included t-tests and Cohen's effect sizes to determine significance and magnitude of changes.
Main Results:
- Overall, a significant small decrease in DSI was observed post-training.
- Athletes with a high initial DSI showed a significant large decrease, while those with a low DSI showed no significant change.
- The decrease in DSI was attributed to increased isometric mid-thigh pull force with minimal change in countermovement jump force.
Conclusions:
- In-season strength training can lead to a decrease in DSI, particularly in athletes with higher baseline DSI.
- The observed changes suggest that strength training enhances maximal force production more than explosive power, altering the DSI.
- These findings have implications for periodization and monitoring training loads in collegiate athletes.
Related Concept Videos
03:05Acid Strength and Molecular Structure
33.1K
Binary Acids and Bases
In the absence of any leveling effect, the acid strength of binary compounds of hydrogen with nonmetals (A) increases as the H-A bond strength decreases down a group in the periodic table. For group 17, the order of increasing acidity is HF < HCl < HBr < HI. Likewise, for group 16, the order of increasing acid strength is H2O < H2S < H2Se < H2Te. Across a row in the periodic table, the acid strength of binary hydrogen compounds increases with increasing...
In the absence of any leveling effect, the acid strength of binary compounds of hydrogen with nonmetals (A) increases as the H-A bond strength decreases down a group in the periodic table. For group 17, the order of increasing acidity is HF < HCl < HBr < HI. Likewise, for group 16, the order of increasing acid strength is H2O < H2S < H2Se < H2Te. Across a row in the periodic table, the acid strength of binary hydrogen compounds increases with increasing...
33.1K
01:20Strength of Cement
499
Strength tests for cement are not performed directly on neat cement paste due to difficulty in obtaining consistent, reliable specimens. Instead, cement is typically tested in the form of cement-sand mortar.
For compressive strength tests, ASTM C 109-05 standards prescribe a cement-sand mix ratio of 1:2.75 and a water/cement ratio of 0.485 for making 2-inch cubes. These cubes are mixed, cast, and cured in saturated lime water at 23°C until testing. Flexural strength testing, outlined in...
For compressive strength tests, ASTM C 109-05 standards prescribe a cement-sand mix ratio of 1:2.75 and a water/cement ratio of 0.485 for making 2-inch cubes. These cubes are mixed, cast, and cured in saturated lime water at 23°C until testing. Flexural strength testing, outlined in...
499
01:30Relation Between Tensile Strength and Compressive Strength of Concrete
672
Concrete is a fundamental building material, and understanding its strengths is crucial for construction projects. The relationship between its tensile and compressive strengths is intricate, showing that while these strengths are related, they do not increase at the same rate. Tensile strength's growth is slower and is affected by various factors such as the methods used for testing, the size and shape of the specimen, the texture of the aggregate used, and the moisture content of the...
672
02:18The Equilibrium Binding Constant and Binding Strength
15.0K
The equilibrium binding constant (Kb) quantifies the strength of a protein-ligand interaction. Kb can be calculated as follows when the reaction is at equilibrium:
15.0K
01:29Strength and Heat of Hydration
687
The hydration of cement is an exothermic reaction in which heat is generated as cement hydrates. This heat of hydration is critical to cement's strength development. The rate at which this heat is generated affects the temperature rise, with a majority of the heat being released early in the hydration process, half within the first three days, and about 75% within the first week.
The heat of hydration for each cement compound is significant; for instance, tricalcium aluminate (C3A) and...
The heat of hydration for each cement compound is significant; for instance, tricalcium aluminate (C3A) and...
687
01:22Fatigue Strength of Concrete
565
Fatigue, in the context of materials science and engineering, refers to the weakening or failure of a material caused by repeatedly applied loads, even if these loads are below the strength limit of the material. Fatigue strength in concrete is a critical property that influences its durability and longevity. Concrete can fail in two ways due to fatigue. Static fatigue or creep rupture occurs under a constant load or one that increases slowly. The other failure mode is due to cyclical or...
565