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Allyson M. Carter, Stephen J. Kinzey, Linda F. Chitwood and Judith L Cole

Context:

Proprioceptive neuromuscular facilitation (PNF) is commonly used before competition to increase range of motion. It is not known how it changes muscle response to rapid length changes.

Objective:

To determine whether PNF alters hamstring muscle activity during response to rapid elongation.

Design:

2 X 2 factorial.

Setting:

Laboratory.

Participants:

Twenty-four women; means: 167.27 cm, 58.92 kg, 21.42 y, 18.41% body fat, 21.06 kg/m2 BMI.

intervention:

Measurements before and after either rest or PNF were compared.

Main Outcome Measures:

Average muscle activity immediately after a rapid and unexpected stretch, 3 times pretreatment and posttreatment, averaged into 2 pre-and post- measures.

Results:

PNF caused decreased activity in the biceps femoris during response to a sudden stretch (P = .04). No differences were found in semitendinosus activity (P = .35).

Conclusions:

Decreased muscle activity likely results from acute desensitization of the muscle spindle, which might increase risk of muscle and tendon injury.

Open access

Christiana M.T. van Loo, Anthony D. Okely, Marijka Batterham, Tina Hinkley, Ulf Ekelund, Soren Brage, John J. Reilly, Gregory E. Peoples, Rachel Jones, Xanne Janssen and Dylan P. Cliff

Background:

To validate the activPAL3 algorithm for predicting metabolic equivalents (TAMETs) and classifying MVPA in 5- to 12-year-old children.

Methods:

Fifty-seven children (9.2 ± 2.3y, 49.1% boys) completed 14 activities including sedentary behaviors (SB), light (LPA) and moderate-to-vigorous physical activities (MVPA). Indirect calorimetry (IC) was used as the criterion measure. Analyses included equivalence testing, Bland-Altman procedures and area under the receiver operating curve (ROC-AUC).

Results:

At the group level, TAMETs were significantly equivalent to IC for handheld e-game, writing/coloring, and standing class activity (P < .05). Overall, TAMETs were overestimated for SB (7.9 ± 6.7%) and LPA (1.9 ± 20.2%) and underestimated for MVPA (27.7 ± 26.6%); however, classification accuracy of MVPA was good (ROC-AUC = 0.86). Limits of agreement were wide for all activities, indicating large individual error (SB: −27.6% to 44.7%; LPA: −47.1% to 51.0%; MVPA: −88.8% to 33.9%).

Conclusions:

TAMETs were accurate for some SB and standing, but were overestimated for overall SB and LPA, and underestimated for MVPA. Accuracy for classifying MVPA was, however, acceptable.

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Lindsey K. Lepley, Abbey C. Thomas, Scott G. McLean and Riann M. Palmieri-Smith

Context:

As individuals returning to activity after anterior cruciate ligament reconstruction (ACLr) likely experience fatigue, understanding how fatigue affects knee-muscle activation patterns during sport-like maneuvers is of clinical importance. Fatigue has been suggested to impair neuromuscular control strategies. As a result, fatigue may place ACLr patients at increased risk of developing posttraumatic osteoarthritis (OA).

Objective:

To determine the effects of fatigue on knee-muscle activity post-ACLr.

Design:

Case control.

Setting:

University laboratory.

Participants:

12 individuals 7–10 mo post-ACLr (7 male, 5 female; age 22.1 ± 4.7 y; 1.8 ± 0.1 m; mass 77.7 ± 11.9 kg) and 13 controls (4 male, 9 female; age 22.9 ± 4.3 y; 1.7 ± 0.1 m; mass 66.9 ± 9.8 kg).

Interventions:

Fatigue was induced via repetitive sets of double-leg squats (n = 8), which were interspersed with sets of single-leg landings (n = 3), until squats were no longer possible.

Main Outcome Measures:

2 × 2 repeated-measures ANOVA was used to detect the main effects of group (ACLr, control) and fatigue state (prefatigue, postfatigue) on quadriceps:hamstring cocontraction index (Q:H CCI).

Results:

All subjects demonstrated higher Q:H CCI at prefatigue compared with postfatigue (F 1,23 = 66.949, P ≤ .001). Q:H CCI did not differ between groups (F 1,23 = 0.599, P = .447).

Conclusions:

The results indicate that regardless of fatigue state, ACLr individuals are capable of restoring muscle-activation patterns similar to those in healthy subjects. As a result, excessive muscle cocontraction, which has been hypothesized as a potential mechanism of posttraumatic OA, may not contribute to joint degeneration after ACLr.

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Yoshifumi Kijima, Ryoji Kiyama, Masaki Sekine, Toshiyo Tamura, Toshiro Fujimoto, Tetsuo Maeda and Tadasu Ohshige

bilateral thigh could estimate whether a stroke patient could walk independently or not. We consider that accelerometers could estimate gait quality relating to gait independence more objectively and in greater detail than simple visual observation. Such additional information would be extremely beneficial

Open access

Tomohiro Yasuda

the American College of Sports Medicine Guidelines for Use of Human Subjects were adopted in this study. The study was approved by the ethics committee of the School of Nursing in Seirei Christopher University. Abe et al 22 revealed that muscle thickness (MT) at the anterior thigh is strongly

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Jan Wilke, Philipp Niemeyer, Daniel Niederer, Robert Schleip and Winfried Banzer

(rolled strokes per minute, Figure  1 ), which has not been investigated before, might represent a more decisive effect modifier. Figure 1 —Foam rolling velocity can be determined by the number of completed strokes per minute. Regarding the anterior thigh, 1 stroke consists of rolling either back or forth

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Amandda de Souza, Cristiano Gomes Sanchotene, Cristiano Moreira da Silva Lopes, Jader Alfredo Beck, Affonso Celso Kulevicz da Silva, Suzana Matheus Pereira and Caroline Ruschel

gains in knee and hip ROM in soccer players immediately after SMR of the anterior and posterior thigh muscles. Mohr et al 19 also verified increased hip-flexion ROM in physically active individuals after SMR of the posterior thigh muscles (3 × 60 s). However, other studies did not find improvements

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Bronwyn K. Clark, Nyssa T. Hadgraft, Takemi Sugiyama and Elisabeth A. Winkler

) was always measured via the activPAL. Two wear positions that researchers using accelerometers often employ to collect movement and posture data (thigh, wrist) were evaluated, with three beacon configurations (wall, desk or both). This enabled evaluation across a range of feasible options (single

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Thomas Haugen, Jørgen Danielsen, Leif Olav Alnes, David McGhie, Øyvind Sandbakk and Gertjan Ettema

specific variables related to front- and back-side mechanics are associated with sprint performance. Figure 1 —Definition of angles. The black dot represents CoM. CoM indicates center of mass; θ trunk , trunk angle relative to horizontal; θ thigh , thigh angle relative to horizontal, where an angle of 0

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Amber Watts, Mauricio Garnier-Villarreal and Paul Gardiner

( Rosenberger et al., 2013 ). Thigh or waist placement of postural monitors have higher rates of accuracy compared to wrist worn monitors ( Janssen & Cliff, 2015 ; Yang & Hsu, 2009 ). The activPAL ™ postural monitor, worn on the thigh, uses both postural angle and acceleration to measure sitting. It can