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ABSTRACT:Kasovic, J, Martin, B, Carzoli, JP, Zourdos, MC, and Fahs, CA. Agreement between the Iron Path app and a linear position transducer for measuring average concentric velocity and range of motion of barbell exercises. J Strength Cond Res 35(2S): S95-S101, 2021-The purpose of this study was to compare average concentric velocity (ACV) and range of motion (ROM) values measured by the Iron Path (IP) app to the previously validated Open Barbell System (OBS) linear position transducer during the front and back squat and conventional and sumo deadlift. Twenty-seven men and women (21 ± 3 years old; 76.7 ± 14.5 kg; 1.72 ± 0.09 m) with squat and deadlift training experience completed a modified one repetition maximum protocol on 4 separate occasions in a randomized order. The IP app and OBS device recorded ACV and ROM during each protocol. The level of statistical significant was set at p ≤ 0.05. Bland-Altman plots showed fairly large limits of agreement for both ACV and ROM. Furthermore, 95% confidence intervals for the intraclass correlation coefficients indicated the agreement in ACV between the devices for each of the 4 lifts to range from 0.648-0.876 to 0.849-0.930 and for agreement in ROM between devices to range from -0.053-0.480 to 0.545-0.770. Compared with the OBS, the IP app recorded significantly (p < 0.05) lower ACV values for the front squat and back squat and greater ROM values for the sumo deadlift. We suggest the IP app should not be used in place of a validated linear position transducer for measuring ACV or ROM for barbell lifts.
The objective of this study was to determine differences in 2 distinct resistance training protocols and if true variability can be detected after accounting for random error. Individuals (n = 151) were randomly assigned to 1 of 3 groups: (I) a traditional exercise group performing 4 sets to failure; (ii) a group performing a 1-repetition maximum (1RM) test; and (iii) a time-matched nonexercise control group. Both exercise groups performed 18 sessions of elbow flexion exercise over 6 weeks. While both training groups increased 1RM strength similarly (similar to 2.4 kg), true variability was only present in the traditional exercise group (true variability = 1.80 kg). Only the 1RM group increased untrained arm 1RM strength (1.5 kg), while only the traditional group increased ultrasound measured muscle thickness (similar to 0.23 cm). Despite these mean increases, no true variability was present for untrained arm strength or muscle hypertrophy in either training group. In conclusion, these findings demonstrate the importance of taking into consideration the magnitude of random error when classifying differential responders, as many studies may be classifying high and low responders as those who have the greatest amount of random error present. Additionally, our mean results demonstrate that strength is largely driven by task specificity, and the crossover effect of strength may be load dependent. Novelty Many studies examining differential responders to exercise do not account for random error. True variability was present in 1RM strength gains, but the variability in muscle hypertrophy and isokinetic strength changes could not be distinguished from random error. The crossover effect of strength may differ based on the protocol employed.
Although often used as a surrogate, comparisons between traditional blood pressure measurements and limb occlusion assessed via hand-held Doppler have yet to be completed. Using limb occlusion pressure as a method of assessing systolic pressure is of interest to those studying the acute effects of blood flow restriction, where the removal of the cuff may alter the physiological response.PURPOSE:We sought to determine how changes in limb occlusion pressure track with changes in traditional assessments of blood pressure.BASIC PROCEDURES:Limb occlusion pressure measured by hand-held Doppler and blood pressure measured by an automatic blood pressure cuff were assessed at rest and following isometric knee extension (post and 5 minutes post).MAIN FINDINGS:Each individual had a similar dispersion from the mean value for both the limb occlusion pressure measurement and traditional systolic blood pressure measurement [BF10: 0.33; median (95% credible interval): 0.02 (-6.0, 5.9) %]. In response to lower body isometric exercise, blood pressure changed across time. The difference between measurements was small at immediately post and 5 minutes post. The Bayes factors were in the direction of the null but did not exceed the threshold needed to accept the null hypothesis. However, at 5 minutes post, the differences were within the range of practical equivalence (within ± 4.6%).PRINCIPAL CONCLUSIONS:Our findings suggest that changes in limb occlusion pressure measured by hand-held Doppler track similarly to traditional measurements of brachial systolic blood pressure following isometric knee extension exercise.
Beck, M, Varner, W, LeVault, L, Boring, J, and Fahs, CA. Decline in unintentional lifting velocity is both load and exercise specific. J Strength Cond Res 34(10): 2709-2714, 2020-When monitoring the mean concentric velocity (MCV) for velocity-based resistance training, often a threshold in the decline in the MCV is used to regulate the number of repetitions performed. However, it is not clear if the decline in the MCV is affected by the type of exercise or the relative load used. Therefore, the purpose of this study was to compare the decline in the MCV between the overhead press (OHP) and deadlift (DL) during sets to fatigue at different loads. Thirty individuals (23 ± 3 years) with current training experience with both the OHP and DL completed a 1 repetition maximum (1RM) protocol for the OHP and DL. Subjects then returned to the laboratory on 2 separate occasions and completed 1 set of the OHP and DL to volitional fatigue at either 70 or 90% of their 1RM in a randomized order. The open barbell system measured the MCV of all repetitions. The absolute and relative (%) decline in the MCV was calculated for each condition and compared between loads (70 vs. 90% 1RM) and between lifts (OHP vs. DL). An alpha level of 0.05 was used at the criterion for statistical significance. The absolute decline in the MCV was greatest for the 70% OHP condition (0.36 ± 0.12 m·s) followed by 90% OHP (0.19 ± 0.10 m·s), 70% DL (0.16 ± 0.08 m·s), and 90% DL (0.09 ± 0.06 m·s); all were significantly different from one another (p < 0.05) except for 70% DL vs. 90% OHP (p = 0.441). There was a greater relative decline in the MCV for the OHP compared with the DL (50.1 ± 11.8% vs. 28.5 ± 11.8%; p < 0.001) and for 70% 1RM compared with 90% 1RM (44.5 ± 12.0% vs. 34.1 ± 12.0%; p < 0.001). These data suggest the decline in the MCV is both exercise and load specific. Applying a uniform velocity decline threshold for velocity-based training may reduce training volume to different extents depending on the exercise and relative load used.
I had been at the library for hours, going over the last edits on my first book (Boyles 2015), when I received a distressing phone call: a police officer had killed a Black male teenager in the city of Ferguson. The caller said protesters were assembling at the scene and suggested that I go there immediately. Well, I responded accordingly. I went, ultimately embarking on an unanticipated, extraordinary three-year empirical journey. As a sociologist and critical criminologist, I had been researching and writing about conflict between Black citizens and police in the suburbs of the St. Louis region for five years. The book I was finalizing was an ethnographic study of Black resident–police relationships in Meacham Park, a historically Black neighborhood in the city of Kirkwood—one of St. Louis’s most exclusive, predominantly white suburbs. In 1991 Meacham Park was annexed by Kirkwood, in what local Black residents described as a land grab. This, together with decades-long racial tensions and inequalities between the two communities, formed the backdrop to two separate shootings, in 2005 and 2008, in which two Black residents killed white police officers and others. The killings shook the region and subjected the residents of Meacham Park to heightened surveillance and harassment. My research extended traditional examinations of racialized policing in urban spaces to examine Black residents’ experiences of policing in suburban locations, such as Ferguson, and how the protests against it form one prong of a larger antiviolence movement in the region. Because Black citizens cross urban boundaries, their experiences with the police are not limited to the inner city. This necessitates critical analyses of the suburbs— especially analyses that uniquely unpack the traditional suburban milieu by accounting for antiurban sentiments and discourse (Low 2001), Black geographies (McKittrick and Woods 2007), and the social control of Black people (Alves 2018), the poor especially. If we attend to the everyday, differential experiences of Black people living in St. Louis suburban municipalities, particularly Kirkwood and Ferguson, the region’s long-standing racial-spatial segregation and containment emerge as the nexus for criminalization, suburban political-economic marginalization, and an unexpected 21st-century Black uprising.
