Assessment of accelerometer-derived data in the context of seat height changes in cycling and the impact on running in triathlon

Triathlon has been an Olympic sport since the 2000 Sydney Olympics and has developed rapidly, leading to variations in race categories. Although running after cycling necessitates a postural change from a non-weight-bearing activity to a weight bearing one, no study has quantified the magnitude of trunk acceleration during cycling in different seat positions and the consequential effect on running. Therefore, this study was conducted to evaluate the effectiveness of a triaxial accelerometer to determine acceleration magnitudes of the trunk in a 20 km outdoor cycling event in two seat positions that were immediately followed by a 5 km overground run. Interpretation of data was evaluated based on cadence changes while triathletes cycled in an aerodynamic position in two seat positions. Running data was evaluated based on sinusoidal curves and foot strike peaks. The evaluation of accelerometer derived data within a characteristic overground setting suggests that cycling in an adjusted seat position significantly reduced trunk acceleration in both longitudinal and mediolateral directions with large effects ( p < 0.0001, d > 0.9). A significant and large effect was found in both longitudinal and anteroposterior trunk acceleration in post-cycle running between seat positions ( d > 0.9, p < 0.0001). In the longitudinal direction, a significant reduction in trunk acceleration occurred when running after the seat was adjusted with participants completing the 5 km run faster (21:55 ± 3:17 min compared to 22:05 ± 2:53 min). The results suggest that when the seat position is adjusted based on individual anthropometrics, overall trunk acceleration magnitude is reduced in both cycling and running. Accessible and practical sensor technology could be beneficial for postural considerations in triathlons.

Enhancing Occupant Safety by Pre-active Seat Control for Out-of-seat Position before Autonomous Emergency Braking Operation

The pre-active safety seat (PSS) is a recently developed active safety system for securing occupant safety in out-of-seat position (OOSP), which was applied in the Hyundai Genesis G80 in 2020. However, there has not been sufficient quantifiable verification supporting the effectiveness of the PSS. The present study was performed to determine the effectiveness of the PSS for occupant safety in OOSP and to identify areas for additional improvement. Six test conditions were considered to determine the effectiveness of the PSS for augmentation of occupant safety in OOSP. Ten healthy men participated in the tests. Compared with the no PSS condition, maximum head excursion and neck rotation were significantly decreased in the PSS condition by 0.31–0.79-fold and 0.33–0.48-fold, respectively (p < 0.05). The PSS condition in which the seat pan was moved forward to the mid position showed a greater effect in reducing the characteristic motions related to submarining, compared with the condition in which the seat pan was moved rearward to the mid position (p < 0.05). These results suggested that PSS augments occupant safety in OOSP. This study provides valuable insights in ameliorating risks to the occupant in unintended seat positions before braking and/or collision.

Effect of Adapted Ergometer Setup and Rowing Speed on Lower Extremity Loading in People with and without Spinal Cord Injury

IntroductionFunctional electrical stimulation assisted rowing (FES-rowing) on an adapted ergometer is used in spinal cord injury (SCI) rehabilitation. A primary goal is to mechanically load the lower extremity to prevent disuse osteoporosis. Recent studies reported the small foot reaction force in FES-rowing was not sufficient to prevent bone loss.ObjectiveThis study aims to investigate the effect of ergometer setup and rowing speed on lower extremity loading in able-bodied and SCI individuals.DesignTwenty able-bodied novice rowers and one experienced SCI rower rowed on an adapted ergometer with different speeds and setups. Motion capture system and force sensors were used to calculate forces and moments at the knee.Main Outcome MeasuresFoot reaction force and knee moment for all participants, and tibiofemoral force of the SCI rower.ResultsPeak foot reaction forces of able-bodied rowers ranged from 0.28 – 0.45 body weights (BW), which was less than half the force in normal rowing. A fast rowing speed, forward seat position, and large knee RoM were associated with higher foot force and knee moment during able-bodied rowing. The SCI subject had the greatest foot reaction force (0.40 BW) when rowing with small knee RoM at a rear seat position and the highest tibiofemoral force (2.23 BW) with large knee RoM at a rear seat position.ConclusionErgometer setup and speed can double the force generation at the foot during both able-bodied rowing and FES-rowing. Rowing forms (range of motion and speed) that resulted in the greatest foot reaction force were different for able-bodied rowers and SCI rowers, indicating a trade-off between motion and force generation in FES-rowing that warrants further investigation with more SCI rowers. Clinicians and physical therapist should be aware that ergometer setups can be easily adjusted to modify rowing forms and loading patterns of users with SCI.

Learning Difficulties in Listening Comprehension

This paper aims at describing the student’s listening skill and their learning difficulties in listening comprehension. The method used was a descriptive method. The instruments were pre-TOEFL test and questionnaire. The population was the second year students of State University of Makassar. The results of this research are: the students have poor score in their listening comprehension and the students' learning difficulties in listening comprehension are: problem in interpretation, the lack of vocabulary, difficulty to concentrate, problem with lecturer's accent, confusion in similar phonemes, the speed of the speech problem in accent, problem in reduction and there are no repetitions and in learning media, the noise from students themselves, unclear sound, air conditioner problems and seat position. Based on the result, the writer concludes that the students' ability in listening comprehension is still poor, the teacher should motivate them to develop the habit of writing daily listening so that they can improve their skill.