The effects of varying inertial loadings on power variables in the flywheel romanian deadlift exercise.

The aim of this study was to investigate the effect of four different inertial loads (0.025, 0.050, 0.075, and 0.100 kg· m²) on concentric (CON) power, eccentric (ECC) power, and ECC overload in the flywheel Romanian deadlift (RDL). Fourteen recreationally trained males (27.9 ± 6.4 years, 90 ± 10.7 kg, 180.7 ± 5.5 cm) volunteered for the study. They had a minimum of two years of resistance training experience, although none had experience in flywheel inertia training (FIT). All participants performed the flywheel RDL on a flywheel device (kBox 3, Exxentric, AB TM, Bromma, Sweden). Each set was performed using different inertial loads, those being 0.025, 0.050, 0.075, and 0.100 kg·m². For CON, ECC power, and ECC overload, there was a significant difference (p < 0.001) between inertial loadings. In conclusion, results highlight that lower inertial load leads to higher peak CON and ECC power values, precisely 0.025 kg· m². Regarding ECC overload, medium to higher loads (0.050, 0.075, and 0.100 kg·m²) will lead to higher values.

Test-Retest Reliability of Single-Leg Time to Stabilization Following a Drop-Landing Task in Healthy Individuals.

CONTEXT: Single-leg stability has been associated with injury risk and is a key component of many injury prevention interventions. Methods of measuring single-leg stability are varied yet often unreliable. OBJECTIVE: To establish within- and between-day test-retest reliability for single-leg time to stabilization (SL-TTS) following a drop-landing maneuver of 20 cm in height among a healthy cohort. DESIGN: Test-retest reliability study. SETTING: Healthy cohort from a third-level educational institution. PARTICIPANTS: Nineteen (11 females and 8 males) healthy individuals. MAIN OUTCOME MEASURES: The SL-TTS in the vertical plane. RESULTS: The SL-TTS showed good within-day (intraclass correlation coefficient = .715) and excellent between-day (intraclass correlation coefficient = .83) test-retest reliability. The minimal detectable change was calculated as 171.6 ms for within-day contexts and 123.8 ms for between-day contexts. CONCLUSIONS: This method of measuring SL-TTS is reliable and could be used to detect changes over time in a healthy cohort. This could be of value to clinicians in injury risk factor identification or assessing the effectiveness of single-leg stability training. However, further research is needed to investigate its reliability in pathological populations.

Effects of the Gaelic Athletic Association 15 on Lower Extremity Injury Incidence and Neuromuscular Functional Outcomes in Collegiate Gaelic Games.

Schlingermann, BE, Lodge, CA, Gissane, C, and Rankin, PM. Effects of the Gaelic Athletic Association 15 on lower extremity injury incidence and neuromuscular functional outcomes in collegiate Gaelic games. J Strength Cond Res 32(7): 1993-2001, 2018-The purpose of this observational analytical cohort study was to assess the effectiveness of an injury prevention program (IPP)-Gaelic Athletic Association 15 (GAA15)-on the incidence of injury in collegiate Gaelic games. One hundred and thirty-one Gaelic games players (mean age 20.5 years ± SD 3.0) were used for analysis in this study. Participants completed preseason and postseason testing which involved performance of the Y-Balance Test. The GAA15 was used for the intervention group; coaches were instructed to implement the program before every training session and match throughout the collegiate Gaelic Athletic Association (GAA) season. The control group adopted their normal warm-up procedures for the season. The players' injuries were documented on a weekly basis by allied health care professionals working with the teams using an online database system. Results showed significant improvements in composite Y-Balance scores in favor of the intervention group (adjusted mean difference Right: 1.8 % normalized mean reach distance (%NMRD) [p = 0.007]/Left: 2.3 %NMRD [p = 0.001]). Injury rates in the intervention group (2.62 injuries per 1,000 hours) were reduced by 66% (p = 0.001) in comparison with an age-matched control group (7.62 per 1,000 hour). Training injuries, hamstring injuries, noncontact injuries, and severe injuries were also reduced as a result of the implementation of the GAA15 (injury rate ratio: 0.20, 0.59, 0.39, and 0.45, respectively). Implementation of an IPP such as the GAA15 can reduce the risk of injury in Gaelic games and influence players' neuromuscular performance assessed through the Y-Balance Test.

The Efficacy of Flywheel Inertia Training to Enhance Hamstring Strength.

The purpose of this narrative review is to examine the efficacy of flywheel inertia training to increase hamstring strength. Hamstring strain injury is common in many sports, and baseline strength deficits have been associated with a higher risk of hamstring strain injury. As a result, strength and conditioning professionals actively seek additional techniques to improve hamstring strength with the aim of minimising the incidence of hamstring strain injury. One method of strength training gaining popularity in hamstring strength development is flywheel inertia training. In this review, we provide a brief overview of flywheel inertia training and its supposed adaptions. Next, we discuss important determinants of flywheel inertia training such as familiarisation, volume prescription, inertia load, technique and specific exercise used. Thereafter, we investigate its effects on hamstring strength, fascicle length and hamstring strain injury reduction. This article proposes that hamstring specific flywheel inertia training can be utilised for strength development, but due to the low number of studies and contrary evidence, more research is needed before a definite conclusion can be made. In addition, as with any training modality, careful consideration should be given to flywheel inertia training determinants. This review provides general recommendations of flywheel inertia training determinants that have value when integrating flywheel inertia training into a hamstring strengthening program.

Intrarater Test-Retest Reliability of Hip Abduction, Internal Rotation, and External Rotation Strength Measurements in a Healthy Cohort Using a Handheld Dynamometer and a Portable Stabilization Device: A Pilot Study.

OBJECTIVE: To investigate the within-day and between-day test-retest reliability of hip abduction, internal rotation, and external rotation strength measurements taken using a portable device externally stabilizing a handheld dynamometer in healthy participants. DESIGN: Observational study. SETTING: Institute of Technology Carlow, Ireland, a third-level education institute. PARTICIPANTS: Healthy participants (N=18; 11 male, 7 female) who participate in a field sport for more than 2 hours per week were recruited via convenience sampling. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Hip abduction, internal rotation, and external rotation peak force during a maximal voluntary isometric contraction (N). The 3 best values recorded for each movement for each day were used to analyze within-day and between-day test-retest reliability. Intraclass correlation coefficients (ICCs), coefficients of variance, standard error of measurement, and minimal detectable change statistics were also calculated. RESULTS: External fixation of a handheld dynamometer produced excellent test-retest reliability for within-day (ICC>0.934) and between-day (ICC>0.802) contexts. CONCLUSIONS: Clinical measurements of hip strength can be performed reliably, efficiently, and cost effectively using the methods described. Furthermore, the use of external fixation eliminates the influence of tester strength on the handheld dynamometry measurements.

Reliability and Validity of a New Eccentric Hamstring Strength Measurement Device.

OBJECTIVE: To investigate the reliability and establish validity of a new eccentric hamstring strength measurement device. DESIGN: A randomized double-crossover trial with intraclass correlation coefficients to analyze the outcomes. Participants attended 4 sessions, 7 days apart. They were randomly allocated into 2 groups. Session 1 was a familiarization session for all participants on the new eccentric hamstring strength measurement device and isokinetic dynamometer. The following 3 sessions were used to measure knee flexor (hamstring) eccentric strength on the isokinetic dynamometer and a further test-retest measurement using the new eccentric hamstring strength measurement device. SETTING: Institute of Technology Carlow, third level educational institution. PARTICIPANTS: Male intercollegiate field-sport players completed the trial (N=19). Participants were 21±2 years, weighed 78.6±4.6 kg, and were 179.6±6.4 cm in height. INTERVENTIONS: N/A. MAIN OUTCOME MEASURES: Peak torque (Nm) was recorded by the isokinetic device, and peak force (N) was recorded by the new eccentric hamstring strength measurement device and used to test for significant interdevice correlations (>0.7). Intraclass correlation coefficients were calculated using the peak force recorded from 2 separate trials of the new eccentric hamstring strength measurement device. RESULTS: High test-retest reliability was observed from the new eccentric hamstring strength measurement device, intraclass coefficient (ICC)=.910 (confidence interval [CI], .76-.96) and .914 (CI, .78-.96) for left and right peak forces, respectively. Typical error of measurement between trials was calculated to be 14.65 and 17.29N for the left and right limbs, respectively. Minimum detectable change (MDC) was also calculated to be 40.62N (MDC%=14.68%) and 39.63N (MDC%=13.31%) for left and right limbs, respectively. The interdevice correlation showed good validity, ICC=.823 (CI, .58-.93) and .840 (CI, .58-.93) for left and right peak torque/forces, respectively. CONCLUSIONS: The new eccentric hamstring strength measurement device is a reliable and valid device that provides an objective measurement of eccentric hamstring strength that may be used in combination with a comprehensive assessment to inform rehabilitation and management.