                  FOR PUBLICATION
  UNITED STATES COURT OF APPEALS
       FOR THE NINTH CIRCUIT

UNITED STATES OF AMERICA,                  No. 11-30099
                 Plaintiff-Appellee,          D.C. No.
                v.                        4:10-CR-00111-
H.B., JUVENILE MALE,                            SEH-2
              Defendant-Appellant.
                                             OPINION

        Appeal from the United States District Court
                for the District of Montana
         Sam E. Haddon, District Judge, Presiding

                   Argued and Submitted
            April 10, 2012—Seattle, Washington

                   Filed August 22, 2012

   Before: Dorothy W. Nelson, A. Wallace Tashima, and
           Consuelo M. Callahan, Circuit Judges.

                  Opinion by Judge Nelson




                            9593
            UNITED STATES v. H.B., JUVENILE MALE        9595




                        COUNSEL

Mark D. Meyer, Ugrin, Alexander, Zadick & Higgins, P.C.,
Great Falls, Montana, for the defendant-appellant.

Laura B. Weiss, Assistant U.S. Attorney, Michael W. Cotter,
United States Attorney, Office of the United States Attorney,
Great Falls, Montana, for the plaintiff-appellee.
9596           UNITED STATES v. H.B., JUVENILE MALE
                               OPINION

NELSON, Senior Circuit Judge:

   H.B. appeals his adjudication as a juvenile delinquent for
aiding and abetting his cousin, W.B., in committing aggra-
vated sexual abuse against their female friend, T.T.W., on an
Indian reservation.1 18 U.S.C. §§ 5031 et seq.; 18 U.S.C.
§ 1153(a); 18 U.S.C. § 2. On appeal, H.B. claims that there
was insufficient evidence to support his adjudication. In addi-
tion, H.B. contends that the district court imposed an unrea-
sonable sentence by ordering him to spend 18 months at a
juvenile correctional detention facility followed by 12 months
of juvenile delinquent supervision. We disagree, and affirm
the adjudication and sentence.

                                     I.

   T.T.W. testified that, late in the evening on October 30,
2009, she went to H.B.’s house to ask for a ride home after
drinking heavily with some friends at a party. The next thing
T.T.W. remembers is waking up in a bed, with no pants or
undergarments on, with W.B. on top of her engaging in sexual
intercourse. T.T.W. then observed H.B. next to her, holding
her right leg down and saying either, “I get next,” or, “I get
dibs.” When T.T.W. realized what was happening, she started
crying, told W.B. to get off of her, and said that she wanted
her clothes.

  At some point during the assault, while T.T.W. was crying,
H.B. and W.B.’s grandfather entered the room to investigate
a noise. W.B. covered T.T.W.’s mouth with his hand and the
boys pulled a blanket over her to conceal her presence. W.B.
“was still doing it to [her]” when the grandfather left the
room.
  1
    We use the initials “H.B.,” “W.B.,” and “T.T.W.” to protect the identi-
ties of the individuals involved in this case, as they were all minors at the
time of the offense.
            UNITED STATES v. H.B., JUVENILE MALE           9597
   Immediately after the incident, T.T.W. gathered her
clothes, left the house, and went to the hospital. The regis-
tered nurse who evaluated her testified that T.T.W. had a
fresh bruise on her left arm. The report from the sexual assault
examination also indicated, under the patient assault history,
that the method used by the assailant included “holding and
pinching,” which it described as “[h]olding legs apart.”

   On the other hand, W.B. testified that he and T.T.W. were
having consensual sex when she “blanked out” and then
“came to” and asked what he was doing. He further testified
that she did not start crying until after he got off of her, and
that they were no longer having sex when his grandfather
came into the room. H.B. testified that he was watching tele-
vision in his grandfather’s living room at the time of the inci-
dent, and only entered the bedroom briefly to retrieve his
telephone. He denied holding T.T.W.’s leg and stating either,
“I get next,” or, “I get dibs.”

   Following a one-day bench trial, the district court adjudged
W.B. and H.B. to be juvenile delinquents. 18 U.S.C. §§ 5031
et. seq. Specifically, the district court found W.B. to be a
juvenile delinquent for “knowingly us[ing] force to cause
[T.T.W.] to engage in a sexual act,” in violation of 18 U.S.C.
§ 2241(a)(1), and adjudged H.B. to be a juvenile delinquent
for “knowingly and intentionally” aiding and abetting W.B. to
commit the act, in violation of 18 U.S.C. § 2. The district
court also found that the offense took place on the Blackfeet
Indian Reservation in Montana, and that H.B. and W.B. are
Native Americans. 18 U.S.C. § 1153(a). In denying W.B. and
H.B.’s motions for acquittal pursuant to Rule 29 of the Fed-
eral Rules of Criminal Procedure, the trial court acknowl-
edged that this case involves disputed facts that rely heavily
on credibility determinations, but found T.T.W.’s testimony
to be more credible and consistent than that of W.B. and H.B.

  At a subsequent dispositional hearing, the district court
ordered H.B. to spend 18 months in detention followed by 12
9598        UNITED STATES v. H.B., JUVENILE MALE
months of juvenile delinquent supervision. Prior to rendering
the sentence, the district court heard testimony from H.B.’s
grandfather and legal guardian, listened to H.B.’s statements,
and solicited comments from H.B.’s counsel and the govern-
ment. H.B.’s grandfather described H.B. as an intelligent, car-
ing individual who overcame adversity after being hit by a car
when he was ten years old. When the government asked
H.B.’s grandfather what type of enhanced structure he would
be able to provide for H.B., should he be granted probation,
H.B.’s grandfather stated only that he would be “more care-
ful.” H.B.’s grandfather also did not know any specific infor-
mation about sex offender treatment programs available in the
area and did not have a program set up for H.B. at the time
of the hearing.

   In explaining its disposition, the district court acknowl-
edged H.B.’s positive qualities, including his intelligence and
ability to graduate from high school despite adversity. The
court also considered the gravity of the offense and stated that
the federal Sentencing Guidelines range for an adult convic-
tion under 18 U.S.C. §§ 1153(a) and 2 would be 235 to 293
months of confinement. The court determined that, in light of
the nature of the offense, H.B. should participate in a sex
offender treatment program and recommended that H.B. be
placed at the Reintegrating Youthful Offenders (“RYO”) Cor-
rectional Facility in Galen, Montana. According to the court,
the RYO facility provides “a safe, secure, and therapeutic
environment for youthful offenders in a location that is closest
to the juvenile’s family in Montana.” Despite the request by
H.B.’s counsel to impose only a 12-month sentence, the dis-
trict court determined that 18 months at the RYO facility was
necessary to provide H.B. with the “structure and time” to
complete the sex offender treatment program and to maximize
his potential rehabilitation.

  H.B. filed a timely appeal.
             UNITED STATES v. H.B., JUVENILE MALE            9599
                               II.

   We have jurisdiction pursuant to 28 U.S.C. § 1291. We
review de novo a trial court’s denial of a Rule 29 motion for
judgment of acquittal. See United States v. Lequire, 672 F.3d
724, 728 (9th Cir. 2012). In determining whether sufficient
evidence exists to support the verdict, we must “first construe
the evidence in the light most favorable to the [government],
and . . . then determine whether any rational trier of fact could
have found the essential elements of the crime beyond a rea-
sonable doubt.” United States v. Shetler, 665 F.3d 1150, 1163
(9th Cir. 2011) (internal quotation marks and citation omit-
ted). When viewing the evidence in the light most favorable
to the government, we “may not usurp the role of the finder
of fact by considering how [we] would have resolved the con-
flicts, made the inferences, or considered the evidence at
trial.” United States v. Nevils, 598 F.3d 1158, 1164 (9th Cir.
2010) (en banc). Therefore, in a case involving factual dis-
putes and credibility determinations, we “must presume . . .
that the trier of fact resolved any such conflicts in favor of the
prosecution, and must defer to that resolution.” Id. (quoting
Jackson v. Virginia, 443 U.S. 307, 326 (1979)).

   We review a juvenile delinquency sentence under the Fed-
eral Juvenile Delinquency Act for abuse of discretion. United
States v. Juvenile, 347 F.3d 778, 784 (9th Cir. 2003).

                               III.

   H.B. appeals the denial of his motion for a judgment of
acquittal. In order for H.B. to be adjudged a juvenile delin-
quent, the government was required to produce sufficient evi-
dence to prove beyond a reasonable doubt that: (1) W.B.
committed the offense of aggravated sexual abuse, 18 U.S.C.
§ 2241(a)(1); (2) H.B. knowingly and intentionally aided and
abetted W.B. in committing each element of the aggravated
offense, 18 U.S.C. § 2; (3) H.B. acted before W.B. completed
the crime; see 9th Cir. Model Crim. Jury Instr. 5.1 (2010)
9600         UNITED STATES v. H.B., JUVENILE MALE
(aiding and abetting); (4) H.B. was under the age of 18 at the
time of the offense, 18 U.S.C. §§ 5031 et. seq.; and (5) H.B.
is a Native American and the offense occurred on the Black-
feet Indian Reservation, 18 U.S.C. § 1153(a).

   H.B. argues on appeal that the government’s evidence was
insufficient to prove beyond a reasonable doubt that W.B.
committed the offense of aggravated sexual abuse. Conse-
quently, the government failed to establish the requisite ele-
ments of H.B.’s aiding and abetting charge. See United States
v. Garcia, 400 F.3d 816, 820 (9th Cir. 2005) (“Aiding and
abetting is not a separate and distinct offense from the under-
lying substantive crime, but is a different theory of liability
for the same offense.”).

   [1] The crime of “aggravated sexual abuse” is proscribed
in 18 U.S.C. § 2241. The statute prohibits “knowingly caus-
[ing] another person to engage in a sexual act by using force
against that other person.” Compare 18 U.S.C. § 2241(a)(1)
(emphasis added), with 18 U.S.C. § 2242 (sexual abuse) (pro-
hibiting individuals from “knowingly . . . caus[ing] another
person to engage in a sexual act by threatening or placing that
other person in fear” or by “engag[ing] in a sexual act with
another person if that other person is . . . physically incapable
of declining participation in, or communicating unwillingness
to engage in, that sexual act . . . .”). The definition of a “sex-
ual act” for purposes of 18 U.S.C. § 2241(a) includes “contact
between the penis and the vulva” which “occurs upon pene-
tration, however, slight.” 18 U.S.C. § 2246(2).

  [2] To render the distinction between sexual abuse and
aggravated sexual abuse meaningful, Section 2241(a)(1) “re-
quires a showing of actual force.” United States v. Fulton, 987
F.2d 631, 633 (9th Cir. 1993). While the statute does not
define “force” or specify how much force is necessary to
amount to a violation, United States v. Lauck, 905 F.2d 15, 17
(2d Cir. 1990), Congress has stated that:
             UNITED STATES v. H.B., JUVENILE MALE              9601
    [t]he requirement of force may be satisfied by a
    showing of the use, or threatened use, of a weapon;
    the use of such physical force as is sufficient to over-
    come, restrain, or injure a person; or the use of a
    threat of harm sufficient to coerce or compel submis-
    sion by the victim.

Sexual Abuse Act of 1986, H. Rep. No. 594, 99th Cong., at
14 n.54a (2d Sess. 1986), reprinted in 1986 U.S.C.C.A.N.
6186, 6194 n.54a. In our few judicial decisions interpreting
the term “force,” we have held that, “the force requirement is
met when the sexual contact resulted from a restraint upon the
other person that was sufficient that the other person could not
escape the sexual contact.” Fulton, 987 F.2d at 633 (internal
quotation marks and citations omitted); United States v. Arch-
dale, 229 F.3d 861, 868 (9th Cir. 2000) (same); see also
United States v. Allery, 139 F.3d 609, 611 (8th Cir. 1998)
(holding that force is sufficient if it “restrain[s] the victim and
allow[s] the defendant to engage in sexual contact”).

   [3] Viewing the evidence in the light most favorable to the
government, a rational trier of fact could conclude that, after
T.T.W. woke up from being “black[ed] out,” W.B. used phys-
ical force sufficient to restrain T.T.W. and engage in an
unwanted sexual act. Specifically, the record supports the rea-
sonable inference that W.B.’s weight on top of T.T.W., com-
bined with his efforts to silence T.T.W. by covering her
mouth with his hand, and H.B.’s physical restraint of
T.T.W.’s right leg, together allowed W.B. to engage in
unwanted sexual contact from which T.T.W. could not escape
immediately. This finding of force is bolstered by the report
from the sexual assault examination taken soon after the
offense, which noted that T.T.W. had a fresh bruise on her left
arm following the incident. In addition, the offense involved
a power disparity in which the two teenage boys acted
together against T.T.W. Cf. Archdale, 229 F.3d at 864, 868
(finding sufficient force for aggravated sexual abuse pursuant
to 18 U.S.C. § 2241(a)(1) to justify a sentencing enhancement
9602        UNITED STATES v. H.B., JUVENILE MALE
where the defendant, who was “six feet tall and over 200
pounds,” grabbed the twelve-year old victim’s head and
moved it “up and down on his penis,” and later “grabbed her
hand above her head, and got on top of her’ ”); see generally
United States v. Lucas, 157 F.3d 998, 1002 (5th Cir. 1998)
(noting that “force can be implied from a disparity in size and
coercive power between the defendant and his victim”).
Therefore, taking the evidence in the light most favorable to
the government, a rational trier of fact could conclude that
W.B. used force to engage in a sexual act with T.T.W.

   [4] In addition, a rational trier of fact could conclude that
H.B. aided and abetted W.B. in committing the offense. H.B.
restrained T.T.W.’s leg while W.B. had sex with her, said
either, “I get next,”or, “I get dibs,” and then helped W.B. in
concealing T.T.W.’s presence from their grandfather. See
United States v. McDaniel, 545 F.2d 642, 644 (9th Cir. 1976)
(aiding and abetting requires “know[ing] that the activity con-
demned by the law is actually occurring and . . . intend[ing]
to help the perpetrator.”).

   [5] While H.B. disputes some of the evidence presented by
the government at trial, the district court’s factual findings
and legal conclusions were supported by its “credibility
assessments” and the “reasonable inference[s]” it drew from
the evidence. Nevils, 598 F.3d at 1167, 1170. Therefore, con-
struing all of the evidence in the light most favorable to the
government, a rational trier of fact could find the essential
elements of H.B.’s charged offense beyond a reasonable
doubt.

                              IV.

   H.B. also claims that the district court imposed an unrea-
sonable sentence by ordering H.B. to spend 18 months in
detention followed by 12 months of juvenile delinquent super-
vision. Specifically, H.B. argues that the district court failed
to give meaningful consideration to the treatment alternatives
            UNITED STATES v. H.B., JUVENILE MALE           9603
authorized by the Federal Juvenile Delinquency Act (FJDA)
by placing H.B. in an overly restrictive environment for an
undue period of time.

   The FJDA, which authorizes federal courts to sentence
juveniles, is intended to remove juveniles from the criminal
justice system and, instead, encourage treatment and rehabili-
tation. Juvenile, 347 F.3d at 785. As a result, “[a] successful
prosecution under the Act . . . results in a civil adjudication
of status, not a criminal conviction.” United States v. Doe, 53
F.3d 1081, 1083 (9th Cir. 1995).

   In fashioning a disposition, a district court “may suspend
the findings of juvenile delinquency, place [the juvenile] on
probation, or commit him to official detention which may
include a term of juvenile delinquent supervision to follow
detention.” 18 U.S.C. § 5037(a). The court also may enter an
order of restitution. Id. When selecting among the dispositions
authorized under Section 5037, the district court must exer-
cise its discretion “in accordance with the rehabilitative func-
tion of the FJDA, which requires an assessment of the totality
of the unique circumstances and rehabilitative needs of each
juvenile.” Juvenile, 347 F.3d at 787.

   [6] In general, “the FJDA disfavors institutionalization and
in particular the warehousing of young people away from
their communities.” Id. at 785; see also 18 U.S.C. § 5039
(“Whenever possible, the Attorney General shall commit a
juvenile to a foster home or community based-facility located
in or near his home community.”). A district court’s disposi-
tion should therefore reflect the least restrictive means of
accomplishing the juvenile’s rehabilitation. Juvenile, 347 F.3d
at 787. Moreover, district courts should “give due consider-
ation to the unique concerns and needs of [Native American
youth],” as they are “disproportionately subject to federal
court jurisdiction for their delinquency offenses” on account
of the structure of the FJDA. Id. at 789 n.10.
9604        UNITED STATES v. H.B., JUVENILE MALE
   [7] In this case, the record reflects that the district court
considered the totality of H.B.’s unique circumstances and
rehabilitative needs in rendering the disposition. The district
court specifically considered H.B.’s positive qualities, the
nature of the offense, H.B.’s need for sex offender treatment,
and the availability of “comprehensive correctional program-
ming and rehabilitation services available” through the RYO,
the only facility of its type in the state.

   [8] While H.B.’s counsel requested that the court impose
a sentence of only 12 months in detention, which counsel
argued would allow H.B. time to complete the majority of the
18-month sex offender treatment program with the remainder
to be completed on an outpatient basis as necessary, the dis-
trict court did not abuse its discretion in ordering H.B. to
spend the full 18 months at the RYO facility. The order of
detention was no longer than necessary to complete the treat-
ment program, and therefore not overly punitive. See id. at
788 (finding seven-year sentence of juvenile unreasonable
where the sentence exceeded what was necessary for treat-
ment by more than five years). Moreover, without any evi-
dence of a concrete alternative treatment plan, recommending
that H.B. be placed at the RYO facility was not overly restric-
tive. See 18 U.S.C. § 5039. Finally, by emphasizing that the
RYO “is [the] closest [facility] to the juvenile’s family in
Montana,” the district court’s disposition reflects consider-
ation of the need to keep H.B. as close as possible to his fam-
ily and community. See Juvenile, 347 F.3d at 789 (finding
problematic a district court’s decision to place juvenile “inor-
dinately far from access to his family, his tribe, and the sup-
port mechanisms he had in the Fort Belknap Indian
Community” without any justification). Thus, the sentence
imposed by the district court was reasonable in light of the
FJDA.

                              V.

  The district court’s adjudication of H.B. as a juvenile delin-
quent is supported by sufficient evidence, and the sentence
            UNITED STATES v. H.B., JUVENILE MALE         9605
imposed is reasonable. Accordingly, the district court’s adju-
dication and sentence are

  AFFIRMED.
