Testing Isometric Strength

In this study, a low-cost and adaptable isometric strength measurement and exercise development system are described. The implemented system consists of mechanical structure, force measurement sensor, electronic circuit, and computer software. Isometric-isotonic (via spring resistance) strength analysis and various exercise programs can be applied with the system. The developed system has a lower cost compared to its counterparts in the literature and has a structure that can be adapted to different machines and measuring methods. The operability and reliability of the isometric strength measurement and exercise development system have been proven by calibration tests.

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Sprint Kayaking Performance Enhancement by Isometric Strength Training Inclusion: A Randomized Controlled Trial

Sports ◽

10.3390/sports9020016 ◽

2021 ◽

Vol 9 (2) ◽

pp. 16

Author(s):

Danny Lum ◽

Tiago M. Barbosa ◽

Govindasamy Balasekaran

Keyword(s):

Strength Training ◽

Bench Press ◽

Performance Enhancement ◽

Controlled Trial ◽

Time Trial ◽

Isometric Strength ◽

Sports Performance ◽

Knee Angle ◽

Randomized Controlled ◽

Main Effect

Performing isometric strength training (IST) can enhance various sports performance. This study compared the effects of including IST on sprint kayaking performance as compared to traditional strength training. Twenty sprint kayaking athletes (age 22 ± 4 year, stature 1.71 ± 0.09 m, body mass 72.0 ± 11.4 kg) performed a 200-m kayak ergometer time trial (200mTT), isometric squat (IsoSqT), isometric bench press (IsoPress) and isometric prone bench pull (IsoPull) during the pre- and post-tests. Athletes were randomly assigned to either traditional strength training (TRAD) or IST group. Both groups performed a similar strength training program twice a week for six weeks. However, half the volume for squat, bench press and prone bench pull were replaced by IsoSqT, IsoPress and IsoPull, respectively, for the IST group. IsoSqT was performed at 90° knee angle, while IsoPress and IsoPull were performed at 90° and 120° elbow angles, respectively. Each isometric contraction was performed with maximum intensity and sustained for three seconds. A significant main time effect was observed for 200mTT (p < 0.001, ƞ2p = 0.68) and all isometric strength measures (p = 0.001–0.032, ƞ2p = 0.24–0.76) except rate of force development at 0–90 ms (RFD90) obtained from IsoSqT120 and IsoPress90. A group main effect was observed in RFD90 obtained from IsoSqT120 and IsoPull120 (p = 0.003–0.004, ƞ2p = 0.37–0.39). Time x Group interaction was observed for 200mTT (p = 0.027, ƞ2p = 0.68), peak force obtained from IsoSqT90, IsoPress90, and IsoPull120 (p = 0.004–0.006, ƞ2p = 0.36–0.38) and RFD90 obtained from IsoSqT120 and IsoPull120 (p = 0.012–0.015, ƞ2p = 0.28–0.30). Inclusion of IST resulted in greater improvement for sprint kayaking and strength performances then TRAD alone.

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ISOKINETIC AND ISOMETRIC STRENGTH IN OSTEOARTHROSIS OF THE KNEE

American Journal of Physical Medicine & Rehabilitation ◽

10.1097/00002060-199509000-00008 ◽

1995 ◽

Vol 74 (5) ◽

pp. 364???368 ◽

Cited By ~ 55

Author(s):

Jale Tan ◽

Nilufer Balci ◽

Vesile Sepici ◽

Fatma Atalay Gener

Keyword(s):

Isometric Strength

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Knee Muscle Strength Recovery in the Early Period After ACL Reconstruction

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967114s00141 ◽

2014 ◽

Vol 2 (11_suppl3) ◽

pp. 2325967114S0014

Author(s):

Gulcan Harput ◽

Hasan Erkan Kılınc ◽

Hamza Özer ◽

Gül Baltacı ◽

Carl G. Mattacola

Keyword(s):

Acl Reconstruction ◽

Early Period ◽

Quadriceps Strength ◽

Isometric Strength ◽

Time Points ◽

Hamstring Muscles ◽

Significant Difference ◽

Isometric Torque ◽

Over Time ◽

Time Point

Objectives: The aim of this study was to investigate quadriceps and hamstrings isometric strength at 4, 8 and 12 week time points following ACL Reconstruction (ACLR) and to document the strength changes of these muscles over time. The primary hypothesis was that there would be significant increases in quadriceps and hamstring muscle strengths between the 4th, 8th and 12th weeks following ACLR. The secondary hypothesis was that the quadriceps index would be higher than hamstring index at 12th week after ACLR. Methods: Thirty patients (Mean ± SD [age, 29.1±2.3yrs; weight, 77.3±13.2kg; height, 172.1±7.1cm; BMI, 21.2±3.5kg/m2, time to surgery: 7.1±7.2 months]) who underwent ACLR with Hamstring Tendon Autograft (HTG) were enrolled in this study. The isometric strength of quadriceps and hamstring muscles was measured on an isokinetic dynamometer at 60° knee flexion angle at 4th, 8th and 12th weeks after surgery. The recovery of quadriceps and hamstring muscles strength following rehabilitation was expressed as a Quadriceps Index (QI) and Hamstring Index (HI) and calculated with the following formula:[(maximum voluntary isometric torque of the involved limb / maximum voluntary isometric torque by uninvolved limb) × 100]. Torque output of the involved and uninvolved limbs and quadriceps and hamstring indexes were used for the statistical analysis. A repeated measures of ANOVA was used to determine the strength changes of quadriceps and hamstrings over time. Results: Quadriceps and Hamstrings strengths significantly increased over time for both involved (Quadriceps: F (2,46)=58.3, p<0.001, Hamstring: F (2,46)=35.7, p<0.001) and uninvolved limb (Quadriceps: F(2,46)=17.9, p<0.001, Hamstring: F(2,46)=56.9, p=0.001 ). Quadriceps strength was higher at 12th week when compared to the 8 and 4 week time points for the involved limb (p<0.001), and it was higher at 8th week when compared to 4 week time point for the involved limb (p<0.001). For the uninvolved limb, quadriceps strength was also higher at 12th week when compared to the 8 (p=0.02) and 4 week time point (p<0.001), and higher at 8 week when compared to the 4 week time point (p=0.02). Hamstring strength was higher at 12 week when compared to the 8 and 4 week time points (p<0.001) and it was higher at 8 week when compared to 4 week time point for the involved limb (p<0.001). For the uninvolved limb hamstring strength was also higher at 12 week when compared to 4 week time point (p=0.01). There was no significant difference between the 4 and 8 week time points (p>0.05) or between the 8 and 12 week time points (p=0.07). Quadriceps and hamstring indexes significantly changed from 4th weeks (QI:57.9, HI:54.4 ) to 8th weeks (QI:78.8, HI:69.9 ) and from 8th weeks to 12th weeks (QI:82, HI:75.7 ) (p<0.001); however, there was no difference between indexes at the 12-week time point (p=0.17). Conclusion: Isometric strength of quadriceps and hamstring muscles for the involved and uninvolved limb increased during the early period of ACLR. The results of this study could be a baseline for clinicians while prescribing a rehabilitation protocol for ACLR patients with HTG to better appreciate expected strength changes of the muscles in the early phase.

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Efeitos da crioterapia e da diatermia por micro-ondas sobre a capacidade de produção de força de flexores de cotovelo de homens saudáveis

Brazilian Journal of Kinanthropometry and Human Performance ◽

10.5007/1980-0037.2016v18n3p332 ◽

2016 ◽

Vol 18 (3) ◽

pp. 332

Author(s):

Juliana Carvalho Schleder ◽

Andrelize Müller ◽

Walkyria Vilas Boas Fernandes ◽

Andrielle Elaine Capote

Keyword(s):

Production Capacity ◽

Peak Strength ◽

Isometric Strength ◽

The Other ◽

Significant Difference ◽

Thermal Changes ◽

Study Participants ◽

Sedentary Subjects ◽

Isometric Muscle ◽

Microwave Diathermy

DOI: http://dx.doi.org/10.5007/1980-0037.2016v18n3p332 Physiological effects of thermal changes in tissues might influence some physical properties of muscle fibers, such as strength. The aim of this study was to compare the effects of cryotherapy and microwave diathermy application on the strength production capacity of the elbow flexor muscles. Thirty male, healthy and sedentary subjects, with average age of 22.40 (±3.42) years, participated in this prospective study. Participants were submitted to assessment of isometric strength production capability by an adapted load cell. Half of volunteers received cryotherapy on the first day of application and microwave diathermy (MD) 48 hours later, whereas the other half was treated the other way around. Cryotherapy was applied up to the temperature of the biceps region reached 25ºC, and MD was applied up to 42ºC. Six peak strength reevaluations were made over 2 hours. There was significant increase in peak strength (PS) up to 15 minutes after cryotherapy, then there was a decrease in maximum isometric strength, however, statistically significant difference remained up to 1 hour and 30 minutes after cryotherapy. In MD, PS decreased significantly after application until 15 min. From this moment, PS returned close to the initial value, and in the last assessment, PS reduced again. Cryotherapy and MD differently interfered in isometric muscle strength production capacity of elbow flexors, while cooling generated increment, heating caused decline.

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Effects of cold water immersion and active recovery on hemodynamics and recovery of muscle strength following resistance exercise

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00151.2015 ◽

2015 ◽

Vol 309 (4) ◽

pp. R389-R398 ◽

Cited By ~ 18

Author(s):

Llion A. Roberts ◽

Makii Muthalib ◽

Jamie Stanley ◽

Glen Lichtwark ◽

Kazunori Nosaka ◽

...

Keyword(s):

Resistance Exercise ◽

Cold Water ◽

Water Immersion ◽

Cold Water Immersion ◽

Isometric Strength ◽

Muscle Temperature ◽

Active Recovery ◽

Recovery Strategies ◽

Postexercise Recovery ◽

Voluntary Contractions

Cold water immersion (CWI) and active recovery (ACT) are frequently used as postexercise recovery strategies. However, the physiological effects of CWI and ACT after resistance exercise are not well characterized. We examined the effects of CWI and ACT on cardiac output (Q̇), muscle oxygenation (SmO2), blood volume (tHb), muscle temperature (Tmuscle), and isometric strength after resistance exercise. On separate days, 10 men performed resistance exercise, followed by 10 min CWI at 10°C or 10 min ACT (low-intensity cycling). Q̇ (7.9 ± 2.7 l) and Tmuscle (2.2 ± 0.8°C) increased, whereas SmO2 (−21.5 ± 8.8%) and tHb (−10.1 ± 7.7 μM) decreased after exercise ( P < 0.05). During CWI, Q̇ (−1.1 ± 0.7 l) and Tmuscle (−6.6 ± 5.3°C) decreased, while tHb (121 ± 77 μM) increased ( P < 0.05). In the hour after CWI, Q̇ and Tmuscle remained low, while tHb also decreased ( P < 0.05). By contrast, during ACT, Q̇ (3.9 ± 2.3 l), Tmuscle (2.2 ± 0.5°C), SmO2 (17.1 ± 5.7%), and tHb (91 ± 66 μM) all increased ( P < 0.05). In the hour after ACT, Tmuscle, and tHb remained high ( P < 0.05). Peak isometric strength during 10-s maximum voluntary contractions (MVCs) did not change significantly after CWI, whereas it decreased after ACT (−30 to −45 Nm; P < 0.05). Muscle deoxygenation time during MVCs increased after ACT ( P < 0.05), but not after CWI. Muscle reoxygenation time after MVCs tended to increase after CWI ( P = 0.052). These findings suggest first that hemodynamics and muscle temperature after resistance exercise are dependent on ambient temperature and metabolic demands with skeletal muscle, and second, that recovery of strength after resistance exercise is independent of changes in hemodynamics and muscle temperature.

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