Evaluation of Shoulder and Knee Isokinetic Strength Profile Among Elite Adolescent Badminton Players

Effect of double rocking jump rope training on lower limb muscle strength of badminton players

BACKGROUND

Double rocking jump rope training can effectively enhance physical recovery, adaptability to exercise load, and lower limb muscle strength of badminton players in sports colleges, thus offering valuable insights for improving training methods in sports colleges and universities.

OBJECTIVE

To investigate the effect of double rocking jump rope training on the lower limb muscle strength of badminton players specializing in badminton in sports colleges.

METHODS

An experimental study was conducted through a ten-week teaching intervention experiment with badminton players. Relevant heart rate indexes and badminton related lower limb muscle strength indexes were measured before and after the experiment. The data of the measured relevant indexes were statistically and analytically analyzed. At the end of the experiment, the physical recovery level and the heart's adaptability to the exercise load of the control group were improved, and the lower limb muscle strength test indexes and sports performance were better than before the experiment. In the experimental group, badminton players' physical function, anaerobic metabolism of the body and other aspects also improved.

RESULTS

The physical function of the experimental group of badminton players, the energy supply capacity of the body anaerobic metabolism and aerobic work capacity all have an enhancement effect, enabling badminton players to adapt to large exercise loads quickly and improve the recovery rate of physical fitness.

CONCLUSION

The introduction of double rocking jump rope into badminton training classes in sports colleges and universities as a means of lower limb muscle strength training is conducive to improving the level of lower limb muscle strength of special badminton players, enriching the teaching and training means of lower limb muscle strength in sports colleges and universities, and broadening the research field of lower limb muscle strength in badminton in sports colleges and universities.

Normative Values of Isometric Shoulder Strength Among Healthy Adults

Background

Normative data is useful for comparing measured values of strength with population norms and can avoid the issues associated with limb symmetry index. The available normative shoulder strength values are limited by constraints on research designs and variability in subject groups which prevents this data being successfully extrapolated to the greater population.

Purpose

The purpose of this study was to establish normative isometric strength values for various movements of the shoulder that are specific to function and rotator cuff strength. A secondary goal of this study was to analyze the effect of age, gender, weight, height, activity level and arm dominance on shoulder strength.

Design

Observational cohort study.

Methods

Subjects in four age groups (20-29, 30-39, 40-49, 50-59) were included in this study-200 males (40.0 ± 11.6 years, 179.1 ± 6.5 cm, 81 ± 13.0 kg) and 200 females (40.1 ± 11.5 years, 165.3 ± 7.4sm, 64.4 ± 11.6 kg). Bilateral isometric strength measurements were taken with a handheld dynamometer testing seven shoulder movements. Tables of normative strength data were constructed. Multivariate analyses were performed to analyze the effects of age, gender, weight, height and activity level on isometric shoulder strength.

Results

Men were stronger than women (p<0.001). Age was not associated with most strength measures with the exception of dominant arm abduction (p<0.004), non-dominant arm abduction (p<0.028) and non-dominant arm scapular plane abduction (p<0.004) which had a negative association with strength. Weight was positively associated with strength (p<0.001). Activity level was positively associated with all strength measures (p<0.05) except dominant sided abduction (p=0.056). There were no statistically significant differences between dominant and non-dominant sides.

Conclusion

This normative data may be useful to the clinician, as it permits a standard against which to compare shoulder strength for various age groups. Clinicians can have confidence that the uninvolved limb, if symptom free, can be used as an adequate benchmark for strength measures.

Levels of Evidence

Level 3©The Author(s).

Shoulder Rotational Strength and Range of Motion in Unilateral and Bilateral Overhead Elite Athletes

CONTEXT

Overhead athletes place tremendous demands on the shoulder complex, which result in adaptive kinematics but potential susceptibility to injury. This study aimed to compare shoulder glenohumeral range of motion (ROM) and rotator muscles strength in bilateral and unilateral overhead sports.

DESIGN

Cross-sectional study; secondary care.

METHODS

Forty-two elite athletes (17.7 [4.5] y; 42.9% female), including 18 swimmers and 24 badminton players, were included. Preseason glenohumeral rotation ROM and isokinetic shoulder internal and external rotator muscles strength was tested (60°·s-1). Bilateral (nondominant:dominant) and agonist:antagonist (external rotator:internal rotator) conventional and functional deceleration ratios (eccentric to concentric) were calculated. The impact of sport and number of competitive years on shoulder ROM and strength was tested.

RESULTS

Badminton players had greater glenohumeral internal rotation deficit, total ROM deficit, and lower bilateral strength ratio than swimmers (P < .050). Rotational strength was positively associated with the competitive years, but greater in swimmers (P < .050) and on the internal rotator (P < .001). The functional deceleration ratio was negatively associated with the competitive years on the dominant side in swimmers and for both sides in badminton.

CONCLUSIONS

Unilateral overhead athletes had greater ROM and rotational strength asymmetries than bilateral athletes. Interestingly, the functional deceleration ratio was lower over time on the dominant shoulder for both sports, but, surprisingly, also on the nondominant shoulder in badminton, potentially creating a greater risk for shoulder injuries.

The Concept of Acceleration and Deceleration in Isokinetics and Its Relation to 3 Hop Tests

CONTEXT

Both isokinetic testing and functional tests are often used during patient rehabilitation programs. Most researchers have assessed the relationship of isokinetic testing and functional tests in parameters such as peak moment, work, or power. However, little information exists regarding the acceleration and deceleration parameters and their relationship to function.

DESIGN

The purpose of the study was to investigate the concept of acceleration and deceleration of the knee flexor and extensor muscle groups during isokinetic testing and its relationship to function.

METHODS

Twenty-six healthy individuals (14 men and 12 women) participated in the study. Isokinetic bilateral concentric knee flexion and extension muscular performance was assessed isokinetically at the angular velocities of 60°/s, 180°/s, and 300°/s. Functional performance was also assessed using (1) single hop for distance, (2) triple hop for distance, and (3) single timed hop. Functional data were normalized to body weight. A P value <.05 was considered to be significant.

RESULTS

Fair and moderate to good correlations (r = .396, P = .045 to r = .705, P = .001) were discovered between flexors' and extensors' acceleration/deceleration variables and the normalized to body weight functional tests.

CONCLUSIONS

Appropriate understanding of isokinetic parameters as described in this study, including acceleration/deceleration values, may provide useful information about the functional ability of the lower limb muscular system.