Objective 2:
Our secondary hypothesis was that at the end of our 4-week intervention, the participants would have an increase in mobility (e.g., squat depth) and muscular endurance (e.g., 60 second squat test), and a positive trend in BPNSFS and psychological (e.g., confidence) outcomes. We conducted a linear mixed model to assess if there were differences in the means at week 1 (i.e., pre), week 4 (i.e., post), and week 8 (i.e., follow-up). For ROM, the test group showed no significant changes from pre (80.05 ± 14.41) to post (77.86 ± 17.83), or pre to follow-up (79.77 ± 14.76). Similarly, the control group did not show significant changes from pre (79.17 ± 13.11) to post (84.64 ± 11.53) or pre to follow-up (79.09 ± 14.97). As shown in
Table 3, there were no significant effects of group, time, or group-by-time interaction. The effect sizes for ROM are reported in
Table 4.
Table 3.
Linear mixed model results for range of motion.
Table 3.
Linear mixed model results for range of motion.
| Time |
Beta |
95% CI |
p-value |
|
| Group |
|
|
|
| Control |
−
|
−
|
−
|
| Test |
1.1
|
−9.7, 12.0
|
0.836
|
| Time |
|
|
|
| Pre |
−
|
−
|
−
|
| Post |
4.4
|
−3.5, 12.0
|
0.270
|
| Follow-up |
−1.2
|
−9.0, 6.7
|
0.771
|
| Group*Time |
|
|
|
| Test*Pos |
−7.4
|
−17, 2.4
|
0.135
|
| Test*Follow-up |
0.06
|
−9.7, 9.8
|
0.990
|
| Note: CI= Confidence Interval |
Table 4.
Effect sizes for range of motion.
Table 4.
Effect sizes for range of motion.
| Time |
Group |
ES |
SE |
df |
Lower CL |
Upper CL |
|
| Pre-Post |
Control |
-0.471 |
0.425 |
55.082 |
-1.322 |
0.381 |
|
| Pre-Follow-up |
Control |
0.124 |
0.423 |
55.082 |
-0.725 |
0.973 |
|
| Post-Follow-up |
Control |
0.594 |
0.429 |
58.667 |
-0.263 |
1.452 |
|
| Pre-Post |
Test |
0.322 |
0.310 |
58.662 |
-0.298 |
0.943 |
|
| Pre-Follow-up |
Test |
0.118 |
0.309 |
58.662 |
-0.501 |
0.737 |
|
| Post-Follow-up |
Test |
-0.205 |
0.302 |
58.662 |
-0.809 |
0.400 |
|
| Time |
Contrast |
ES |
SE |
df |
Lower CL |
Upper CL |
|
| Pre |
Control-Test |
-0.120 |
0.578 |
55.082 |
-1.279 |
1.038 |
|
| Post |
Control-Test |
0.672 |
0.592 |
58.662 |
-0.512 |
1.857 |
|
| Follow-Up |
Control-Test |
-0.127 |
0.590 |
58.662 |
-1.307 |
1.054 |
|
| Note: ES=effect size; SE=standard error; CL=confidence limits |
Additionally, muscular endurance was analyzed using a linear mixed model (
Table 5). The analysis for the test group showed a non-significant result between pre (37.18± 10.31) to post (41.05± 8.92), and pre to follow-up (42.09± 11.14). Similarly, the control group did not show significant changes from pre (35.42± 7.35), to post (44.36± 7.95), or pre to follow-up (41.64± 8.73). As shown in Figures 4 and
Table 5, there were no significant effects of group, time, or group-by-time interaction. The effect sizes for muscular endurance are reported in
Table 6 and the difference-in-difference results are shown in
Table 7.
Table 5.
Linear mixed model results for muscular endurance.
Table 5.
Linear mixed model results for muscular endurance.
| Characteristic |
Beta |
95% CI |
p-value |
|
| Group |
|
|
|
|
| Control |
– |
– |
– |
|
| Test |
1.5 |
−5.3, 8.2 |
0.666 |
|
| Time |
|
|
|
|
| Pre |
– |
– |
– |
|
| Post |
9.3 |
−3.4, 15.0 |
0.002 |
|
| Follow-up |
6.5 |
0.69, 12.0 |
0.029 |
|
| Group*Time |
|
|
|
|
| Test*Post |
−5.2 |
−12, 2.1 |
0.135 |
|
| Test*Follow-up |
−1.4 |
−8.6, 5.8 |
0.699 |
|
| Note: CI= Confidence Interval |
Table 6.
Effect sizes for muscular endurance.
Table 6.
Effect sizes for muscular endurance.
| Time |
Group |
ES |
SE |
df |
Lower CL |
Upper CL |
|
| Pre-Post |
Control |
-1.334 |
0.433 |
67.344 |
-2.198 |
-0.469 |
|
| Pre-(Follow-up) |
Control |
-0.941 |
0.428 |
67.344 |
-1.795 |
-0.088 |
|
| Post-(Follow-up) |
Control |
0.393 |
0.427 |
70.878 |
-0.460 |
1.245 |
|
| Pre-Post |
Test |
-0.588 |
0.311 |
70.864 |
-1.207 |
0.031 |
|
| Pre-(Follow-up) |
Test |
-0.739 |
0.312 |
70.864 |
-1.361 |
-0.116 |
|
| Post-(Follow-up) |
Test |
-0.150 |
0.302 |
70.864 |
-0.752 |
0.451 |
|
| Contrast |
Time |
ES |
SE |
df |
Lower CL |
Upper CL |
|
| Control-Test |
Pre |
-0.211 |
0.487 |
67.344 |
-1.183 |
0.761 |
|
| Control-Test |
Post |
0.535 |
0.501 |
70.864 |
-0.464 |
1.533 |
|
| Control-Test |
Follow-up |
-0.008 |
0.499 |
70.864 |
-1.003 |
0.987 |
|
| Note: ES=effect size; SE=standard error; CL=confidence limits |
Table 7.
Difference-in-difference results for muscular endurance.
Table 7.
Difference-in-difference results for muscular endurance.
| Group |
Time |
EST |
SE |
df |
t ratio |
p-value |
|
| Test-Control |
Post-Pre |
-0.211 |
3.63 |
62.67 |
-1.43 |
0.158 |
|
| Test-Control |
(Follow-up)-Pre |
0.535 |
3.63 |
62.67 |
-0.39 |
0.699 |
|
| Test-Control |
(Follow-up)-Post |
-0.008 |
3.63 |
60.40 |
1.04 |
0.303 |
|
| Note: SE=standard error; EST=estimate |
The BPNSFS was used to assess changes in psychological need satisfaction from pre- to post-intervention. In the test group, the mean psychological need satisfaction decreased slightly from 36.5 (SD = 5.94) at pre-intervention to 34.4 (SD = 7.77) at post-intervention. However, this change was not statistically significant (t(22) = 1.002, p = 0.322). In the control group, the mean psychological need satisfaction increased marginally from 35.9 (SD = 7.06) at pre-intervention to 36.4 (SD = 4.61) at post-intervention, but this difference was also not statistically significant (t(10) = −0.178, p = 0.860).
Moreover, psychological need frustration was explored. In the test group, the mean frustration score decreased from 36.5 (SD = 5.94) at pre-intervention to 20.36 (SD = 7.43) at post-intervention. However, this decrease was not statistically significant (t(22)=−0.445, p = 0.658). The control group’s frustration score also decreased, from 20.09 (SD = 9.181) at pre-intervention to 16.90 (SD = 7.40) at post-intervention, but this difference was not significant (t(10) = −0.894, p = 0.382).
Additionally, a regression was performed to determine if confidence to squat at post-intervention was predicted by squat knowledge at pre-intervention for the entire sample. The regression was significant (F(14,17)=2.337,
p = 0.049), indicating that baseline squat experience accounted for 37.65% (adjusted R
2 = 0.3765) of the variance in squat confidence outcomes. Squat confidence for the test group decreased slightly from pre-intervention (m=0.82m=0.82, SD = 0.38) to post-intervention (
m = 0.77,
SD = 0.42). In the control group, squat confidence also decreased from pre-intervention (
m = 0.81,
SD = 0.40) to post-intervention (
m = 0.45,
SD = 0.52).
Figure 5 shows these changes in squat confidence from pre- to post-intervention for both test and control groups. Although both groups experienced a decrease in confidence, these changes were not statistically significant (p > 0.05).
Finally, the relationship between the BPNSFS score at baseline and squat outcomes at post-intervention was examined. The BPNSFS score was not a significant predictor of squat confidence (F(7,24) = 0.861,
p = 0.550), range of motion (F(1,31) = 1.044,
p = 0.314), or repetitions (F(1,31) = 0.860,
p = 0.360).
Figure 6 illustrates that BPNSFS scores were not significant predictors of post-intervention squat outcomes, including confidence, range of motion, or repetitions (all
p > .05), indicating that psychological need satisfaction at baseline did not significantly influence these outcomes. any of the measured squat outcomes.
Objective 3: Exploratory data
In addition to measuring squat metrics, participant preferences for coaching styles were also measured via a survey in week 4. 17 participants indicated during past experiences they most enjoyed male coaches. Similarly, 16 participants indicated female coaches. However, 60% of participants indicated no preference for a coach’s gender. Participants prioritized leadership and team management over tactical analysis, indicating a preference for coaches who foster teamwork. This data is shown in
Figure 7.
Figure 7: Participant preference for coaching values.