experiencing pain, and for 76% of riders this pain was in the lower back. 3 Kraft et al 4 postulated that the cause of low back pain in riders might be an overuse syndrome of the lumbar spine as a result of the repetitive compressive, torsional, and bending loads absorbed by the rider. 5 The authors used
Catherine Mason and Matt Greig
Jeffrey M. McBride, Tony R. Larkin, Andrea M. Dayne, Tracie L. Haines, and Tyler J. Kirby
The purpose of this investigation was to determine the effect of stable and unstable conditions on one repetition maximum strength and muscle activity during dynamic squatting using absolute and relative loading.
Ten recreationally weight-trained males participated in this study (age = 24.1 ± 2.0 y, height = 178.0 ± 5.6 cm, body mass = 83.7 ± 13.4 kg, 1RM/body mass = 1.53 ± 0.31), which involved two laboratory sessions separated by 1 wk. Linear position transducers were used to track bar displacement while subjects stood on a force plate for all trials. Vastus lateralis (VL), biceps femoris (BF) and erector spinae (L1) muscle activity (average integrated EMG [IEMG]) was also recorded during all trials. During the frst session subjects complete a one repetition maximum test in a stable dynamic squat (S1RM = 128.0 ± 31.4 kg) and an unstable dynamic squat (U1RM = 83.8 ± 17.3 kg) in a randomized order with a 30-min rest period between conditions. The second session consisted of the performance of three trials each for 12 different conditions (unstable and stable squats using three different absolute loads [six conditions] and unstable and stable squats using three different relative loads [six conditions]).
Results revealed a statistically significant difference between S1RM and U1RM values (P < .05). The stable trials resulted in the same or a significantly higher value for VL, BF and L1 muscle activity in comparison with the unstable trials for all twelve conditions.
Unstable squatting is of equal or less (depending on the loading condition) benefit to improving or maximizing muscle activity during resistance exercise.
Michael A. Hunt, Christopher K. Cochrane, Andrew M. Schmidt, Honglin Zhang, David J. Stockton, Alec H. Black, and David R. Wilson
-risk treatments that are potentially disease modifying and suitable for younger patients with knee OA are urgently needed. Unbalanced loading within the tibiofemoral joint is a known risk factor for knee OA progression; 3 – 5 therefore, interventions that redistribute these loads are actively sought. Recent
Shlomo Hammer, Elad Spitzer, and Shmuel Springer
individuals, AT is an overuse injury caused by excessive mechanical loading. 2 , 3 In most cases, nonsurgical strategies are the first line for treatment of AT. 2 These strategies refer to factors that may affect Achilles tendon loading, such as altering excessive training regimes, replacing footwear, and
Erika Zemková, Alena Cepková, and José M. Muyor
directions. Another alternative represents external perturbations applied directly to the body, for example, by pushing/pulling the trunk, shoulders, or pelvis ( Visser, Carpenter, van der Kooij, & Bloem, 2008 ). An example is instrumented tests that consist of trunk repositioning and load release tasks
al., 2005 ). Interestingly, subelite athletes report significantly lower PT (14.4% for volleyball), suggesting that the volume or intensity of loading contributes to the development of this chronic problem ( Hagglund et al., 2011 ; Janssen et al., 2015 ). PT is especially common in professional basketball
Justin J. Merrigan, James J. Tufano, Michael Falzone, and Margaret T. Jones
, which require long rest periods (eg, 7–10 min) to counter the fatigue. 1 Accentuated eccentric loading (AEL), 2 , 3 where eccentric loads are greater in comparison to concentric loads has been shown to increase force, velocity, and power during an exercise 2 , 4 without the need for extended rest
David L. Carey, Justin Crow, Kok-Leong Ong, Peter Blanch, Meg E. Morris, Ben J. Dascombe, and Kay M. Crossley
Training-load prescription in team-sport athletes is a balance between performance improvement 1 , 2 and injury-risk reduction. 3 – 6 The manipulation of training intensity, duration, and frequency to induce improvements in athletic performance is a fundamental objective of training
Franco M. Impellizzeri, Samuele M. Marcora, and Aaron J. Coutts
The concepts of internal and external training load were first presented at the Eighth Annual Congress of the European College of Sport Science in Salzburg, Austria (2003) 1 at an invited session and symposium organized by Tom Reilly. The content of this presentation was included in 2 follow
Håvard Wiig, Thor Einar Andersen, Live S. Luteberget, and Matt Spencer
Monitoring and managing training load may assist to achieve the desired training outcome 1 and reduce injury risk. 2 , 3 However, quantifying training load accurately and reliably is challenging in team sports due to the complexity of movements and actions, and the constant shifting intensities